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Ⅰ What is a Crankshaft Position SensorⅡ Function and Location of Crankshaft Position SensorsⅢ How does a Crankshaft Position Sensor WorkⅣ Symptoms of a Bad Crankshaft Position Sensor4.1 Engine Vibrations4.2 Check Engine Light4.3 Weak Engine Performance4.4 Trouble Starting Car4.5 Engine Stalling4.6 Cylinder MisfiringⅤ How to Replace a Crankshaft Position SensorⅥ Frequently Asked Questions about Crankshaft Position Sensor Ⅰ What is a Crankshaft Position SensorThe engine, together with its components such as the crankshaft position sensor, is one of the most critical aspects of your car. Internal combustion engines are found in almost all modern cars. The crankshaft position sensor is responsible for keeping track of the engine's many moving parts, such as the crankshaft, valves, and pistons. It keeps track of the crankshaft's position and rotational speed, sending the data to the engine management unit so it can make modifications based on operating conditions. Engine management systems employ this information to govern fuel injection, ignition system timing, and other engine characteristics. On petrol engines, the distributor had to be manually set to a timing mark before electronic crank sensors were available. Video. Crankshaft Position Sensor Testing and Replacement Ⅱ Function and Location of Crankshaft Position SensorsThe crankshaft position sensor's primary function is to determine the crank's position or rotational speed (RPM). The information sent by the sensor is used by Engine Control Units to control factors like ignition and fuel injection timing. The sensor will control the fuel injection in a diesel engine. The sensor output may also be linked to other sensor data, such as the cam position, to determine the current combustion cycle, which is critical for a four-stroke engine's beginning. Figure1. Location of Crankshaft Position Sensor The crankshaft position sensor can be found in different places depending on the vehicle. It needs to be close to the crankshaft, therefore it's usually found on the engine's front underbelly. The timing cover is often where you'll find it mounted. It may be positioned on the engine's back or side. The clutch flywheel speed is sometimes used to determine the crankshaft speed using the crankshaft position sensor. The sensor is attached to the transmission's bell housing in these circumstances. Ⅲ How does a Crankshaft Position Sensor WorkThe teeth on the reduction ring attached to the crankshaft pass near to the sensor tip on the crankshaft position sensor. One or more teeth are missing from the reduction ring, which serves as a reference point for the engine computer (PCM). The sensor generates a pulsed voltage signal when the crankshaft spins, with each pulse corresponding to a tooth on the reduction ring. With the engine idling, the photo below displays the actual signal from the crankshaft position sensor. As you can see from the graph, the reduction ring in this vehicle has two missing teeth. Figure2. How a Crankshaft Position Sensor Works The PCM uses the signal from the crankshaft position sensor to determine when and in which cylinder to fire the spark. The signal from the crankshaft position is also utilized to check for misfires in any of the cylinders. There will be no spark and the fuel injectors will not operate if the sensor signal is missing. Magnetic sensors with a pick-up coil that produce A/C voltage and Hall-effect sensors that produce a digital square wave signal, as shown in the photo above, are the two most prevalent varieties. Hall-effect sensors are used in modern automobiles. A two-pin connector is found on a pick-up coil sensor. A three-pin connector is used to connect the Hall-effect sensor (reference voltage, ground, and signal). Figure3. Crankshaft position sensor signal Ⅳ Symptoms of a Bad Crankshaft Position SensorCrankshaft speed and position are critical elements in engine management calculations, and many engines will not start if the crankshaft position sensor does not provide an accurate signal. A malfunctioning crankshaft position sensor usually causes a few symptoms that alert the driver to a potential problem that needs to be addressed. 4.1 Engine Vibrations Figure4. Engine Vibrations Vibrations originating from the engine are another indicator of a malfunctioning crankshaft position sensor. Some people believe that when the engine is running, there is always some vibration emanating from under the hood. If you observe a significant increase in vibration, it could be due to an issue with the crankshaft position sensor. This vibration is frequently accompanied by a significant reduction in fuel economy and power. To get where you need to go, you'll need a lot more power and gas. 4.2 Check Engine Light Figure5. Check Engine Light The crankshaft position sensor is constantly communicated with by the engine control unit. If there is ever a problem with the sensor, the computer will receive incorrect information about the crankshaft's speed and location. This will cause engine malfunctions, resulting in the Check Engine warning light on the dashboard turning on. One of the first signs of a malfunctioning crankshaft position sensor should be this. P0335 is a typical error code that may appear. 4.3 Weak Engine Performance Figure6. Weak Engine Performance Your engine control unit will not know the right position of the crankshaft or cylinders if the crankshaft position sensor is damaged. This will cause the control unit's ability to maintain the engine's functioning and performance to be delayed. During this time, there will be moments of hesitancy every time you press harder on the gas pedal. It may or may not respond at all. On a road where you must move quicker without hesitating, this can be quite risky. 4.4 Trouble Starting Car Figure7. Trouble Starting Car Another major warning flag is that you are having trouble starting your vehicle. When you try to start your car, the crankshaft position sensor immediately starts measuring the crankshaft's position and speed. It receives a specific malfunction code from the sensor, indicating that there is an issue with its operation. When you try to start your vehicle while this problem is present, the engine will be more difficult to start. You may not be able to start your engine at all if the problem persists. 4.5 Engine Stalling Figure8. Engine Stalling One day, you may be cruising along when your engine suddenly stops running. When you have a defective crankshaft position sensor, this is known as engine stalling, and it can happen very frequently. If this sensor is not replaced soon, your engine will eventually stop working. You'll have no choice but to have your car towed to a repair to have the sensor changed. 4.6 Cylinder Misfiring Figure9. Cylinder Misfiring If the crankshaft position sensor fails, the engine control unit will not be able to reliably communicate data about the piston position. A misfire in one or more of the chamber cylinders is common as a result of this. A faulty spark plug can also cause this, but if you're experiencing any of these additional symptoms, don't discount out a bad crankshaft position sensor. Ⅴ How to Replace a Crankshaft Position SensorStart by looking for the sensor, which you can do by inspecting the engine and looking for any sensor that matches the new sensor you just bought at the lower level. Materials:shop lightcarburetor cleanerplastic clipcleaner Tools:small wrench or socketsmall pick or standard screwdriver Step1 Disconnect the BatteryIt's a good idea to disconnect the battery whenever you're working on the engine's inner workings to avoid a short circuit in the car's electrical system. Remove the disarm plug for the main battery pack on hybrid vehicles as well. The location can be found in your owner's manual. Figure10. Disconnect the Battery Step2 Clear Access to the SensorThis crank sensor is located behind the starter motor, which must be removed to access the sensor. When working beneath the car, use a shop light to see what you're doing. Figure11. Clear Access to the Sensor Step3 Inspect the Sensor LocationBecause of the transmission cooling lines, this sensor is difficult to notice, although it is located on the side of the block with the electrical connector attached. If the crankshaft angle sensor is oily, this is a good opportunity to clean it out with a small bit of carburetor cleaner to get a fresh start on the work. Figure12. Inspect the Sensor Location Step4 Release the Electrical ConnectorA plastic clip will hold an electrical hookup to the sensor, which you must push down or pull outward to disengage. Wiggle the connector away from the sensor gently once this is done. This connector can become stuck due to the weather pack seal, which helps keep water out of the sensor terminals, causing corrosion. After removing the connector, inspect it for rust and clean or replace the pigtail if necessary. The engine will stall due to this issue alone. Figure13. Release the Electrical Connector Step5 Remove the Sensor Mount BoltThe majority of crankshaft sensors only have one mounting bolt, which is usually a 10mm bolt. Remove the bolt with a tiny wrench or socket by rotating it counterclockwise and storing it to the side. Figure14. Remove the Sensor Mount Bolt Step6 Remove the SensorBecause the crank sensor has a long stem that can get jammed in the block, removing it can be difficult. To push the sensor mounting tab away, insert a small pick or a regular screwdriver beneath it. Applying too much pressure on these sensors can lead them to break, leaving a piece of the sensor inside the block. When this happens, you can either press the broken piece inward so it falls into the oil pan and stays there, or you can remove the oil pan and remove the broken piece. Figure15. Remove the SensorOnce the sensor is free, take a firm grip on it and twist it away from the engine block. On the sensor, there will be a sealing O ring that will need to be replaced with the new sensor. A new O ring is included with most new sensors. Figure16. Old Crankshaft Position Sensor Step7 Match the New Crankshaft SensorWipe away any grease from the old sensor so you can notice any design differences in the new sensor. When installing new sensors, such as mounting tabs, minor design adjustments are common. The length of the sensor stem can be variable because if it is too long, it will contact the crankshaft, and if it is too short, it will not read accurately. Figure17 .Match the New Crankshaft Sensor Step8 Installing the New Crank Position SensorClean the position sensor porthole with a shop towel before inserting the new sensor to ensure a proper seal to the new sensor O ring. Because there will be motor oil in this port, do not spray carburetor cleaning within it. To help with the cleaning, spray cleaner on the shop towel. Figure18. Sensor Port Place the new crank sensor in the sensor port hole squarely and firmly while matching the mounting plate hole with the threaded bolt hole in the block. Then, by hand, thread in the mounting bolt by turning it clockwise to avoid cross-threading. To avoid damaging the O ring seal and causing an oil leak, lube it with a tiny amount of clean engine oil or WD40. Thread the mounting bolt into place once the sensor has been placed and tighten to around 2-3 foot-pounds. Figure19. Install New Cranks Angle Sensor Push the electrical connector into position while listening for a click to indicate that it has been properly placed and is ready to use.Figure .Install Crankshaft Angle Sensor Connector Step9 Reconnect the BatteryWhen you're done, take the car off the jack stands and rejoin the negative battery cable, and you're ready to go. Figure20. Reconnect the Battery Ⅵ Frequently Asked Questions about Crankshaft Position SensorHow much does it cost to replace a crankshaft position sensor?The average cost for crankshaft position sensor replacement is between $178 and $226. Labor costs are estimated between $98 and $123 while parts are priced between $81 and $103. How long does it take to replace crankshaft sensor?The engine still may run poorly, either way find a good mechanic, one who specializes in engine performance, and set an appointment – the sooner the better. In most instances, this repair should take no longer than one day. Does a crankshaft sensor have to be programmed?No, they do not have to be programmed. After the replacement you should cancel the code and see if it comes back. What happens if you don't relearn crankshaft position sensor?Failure to do such will result in over revving of the engine, causing possible engine damage. 8. Once the engine has returned to idle, check the status of Diagnostic trouble code P1336. If the scanner indicates that the CASE has been learned, the relearn procedure is now complete. 

IntroductionWith the advancement of automobile technology, an increasing number of cars are equipped with car tire pressure monitoring systems, which provide us with a quick and real-time understanding of the car tire pressure, and we no longer have to worry about insufficient and excessive tire pressure before driving, and the car tire pressure monitoring system has brought great convenience to our car. Currently, most car tires are equipped with pressure sensors to detect pressure changes in order to ensure the safety of car driving. According to relevant statistics, tire pressure reaches a reasonable value, which can not only improve driving safety but also reduce fuel consumption. So, how does a car tire pressure sensor work? This article will introduce in detail.Video: Tire Pressure Sensors CatalogIntroductionⅠ Principles of Tire Pressure Sensors in AutomobilesⅡ Design Background of TPMSⅢ Tire Pressure Sensors in a Tire Pressure Monitoring SystemⅣ Details of Tire Pressure Sensors in Direct Tire Pressure Monitoring SystemⅤ SummaryⅥ Frequently Asked Questions about Tire Pressure Sensors Ⅰ Principles of Tire Pressure Sensors in Automobiles1.Strain Sensors in AutomobilesThe principle of a strain sensor is primarily based on the resistive strain effect,when the conductor undergoes mechanical deformation due to external action, a corresponding change in resistance value occurs. Calculate the required pressure by first calculating the magnitude of strain using the relationship between the change in resistance value and the change in output electrical signal. The strain gauge pressure sensor is primarily used to measure the dynamic or static pressure of a flowing medium, such as the inlet and outlet gas or liquid pressure of power pipeline equipment, engine pressure, internal combustion engine pipeline pressure, and so on.The most widely used strain gauge is the paste strain gauge (strain gauge). Its main disadvantages are small output signal, narrow linear range, and poor dynamic response (see resistance strain gauge, semiconductor strain gauge). However, due to the small size of strain gauge, many specifications of commercial strain gauge can be selected, and the form of elastic sensor can be flexibly designed to adapt to various applications, strain type pressure sensor made by strain gauge is still widely used. According to the different structure of elastic sensor, strain type pressure sensor can be roughly divided into strain tube type, diaphragm type, strain beam type and combined type.Figure:Strain Sensors in Automobiles 2.Piezoresistive Pressure Sensors in AutomobilesThe piezoresistive pressure sensor's pressure sensitive element is a piezoresistive element that operates on the piezoresistive effect. The term "piezoresistive element" actually refers to the diffusion resistance created by integrated circuit technology on a semiconductor substrate. When subjected to external force, its resistance changes due to resistivity change. During normal operation, diffusion resistors must be attached to elastic elements, and monocrystalline silicon diaphragms are commonly used.The piezoresistive pressure sensor's main advantages are its small size, relatively simple structure, good dynamic response, high sensitivity, and ability to measure micro pressures of more than ten Pascals. It is a relatively ideal one, and it is currently being developed and applied at a rapid pace. Sensor of pressure. Non-linearity and temperature affect the measurement accuracy of this sensor, affecting the size of the piezoresistive coefficient. Microprocessors are used in today's intelligent piezoresistive pressure sensor to compensate for nonlinearity and temperature. It integrates the sensor and computer on the same silicon chip using large-scale integrated circuit technology, and it has functions such as signal detection, processing, and memory. As a result, the sensor's stability and measurement accuracy are greatly improved.Figure:Piezoresistive Pressure Sensor 3.Other Automotive Pressure SensorsFurthermore, differential transformer type pressure sensors (LVDT) and surface elastic wave pressure sensors are available (SAW). SAW type pressure sensors have small size, light weight, low power consumption, high reliability, high sensitivity, high resolution, digital output, and so on. LVDT type pressure sensors have larger output, easy to digital output, but poor anti-interference. It is used to detect the pressure of an automobile suction valve and can operate reliably in high temperatures. Ⅱ Design Background of TPMSThe tire pressure influences both the car's excellent performance and the length of the tire's service life. According to SAE (Society of Automotive Engineers) data, there are more than 260,000 traffic accidents caused by tire failure in the United States each year, with flat tires accounting for 70% of highway accidents. Furthermore, natural tire leakage or under-inflation is the leading cause of tire failure. Every year, approximately 75% of tire failures occur. The data also shows that in high-speed driving, punctures caused by tire failure are a major cause of traffic accidents.Flat tires, the unseen killer, have caused numerous human tragedies and incalculable economic losses to the country and businesses. As a result, in order to reduce the number of traffic accidents caused by flat tires, the US federal government has mandated that automakers accelerate the development of TPMS ( Tire Pressure Monitoring System).Figure:Tire Pressure Monitoring System Ⅲ Tire Pressure Sensors in a Tire Pressure Monitoring SystemThere are two main tire pressure monitoring system solutions: direct system and indirect system.The direct tire pressure monitoring system measures tire pressure directly using the pressure sensor installed in each tire and displays and monitors the tire pressure. The system will automatically alert if the tire pressure is too low or if there is a leak.To monitor tire pressure, the indirect tire pressure monitoring system compares the speed difference between tires using the wheel speed sensor of the automobile abs system.The main disadvantages of this type of system are as follows: 1. The accurate instantaneous air pressure value of each tire cannot be displayed; 2. It is not possible to alarm when the pressure of the same axle, same side wheel, or all tires drops at the same time; and 3. Factors such as vehicle speed and detection accuracy cannot be taken into account simultaneously.Figure:Tire Pressure Sensors in a TPMS Ⅳ Details of Tire Pressure Sensors in Direct Tire Pressure Monitoring SystemThere are two types of direct tire pressure monitoring systems: active and passive.The active system makes capacitive or piezoresistive pressure sensors on silicon using mems technology. Each rim has a pressure sensor, and the signal is transmitted via radio frequency. It is set up in the wireless cab. The pressure sensitive signal is received by the receiving device, which then displays the current tire pressure after some signal processing.The advantage of active technology is that it is relatively mature, and the modules developed can be applied to tires of various brands, but the disadvantages are also more noticeable. Its induction module requires battery power, posing a problem with system service life.The passive tire pressure monitoring system's sensor is based on surface acoustic waves. A radio frequency electric field is used to generate a surface acoustic wave in this sensor. The surface acoustic wave changes as it passes through the surface of the piezoelectric substrate material. The change in the surface acoustic wave can indicate tire pressure. Although this technology does not require battery power, it does necessitate the integration of the transponder into the tire, and it can only be implemented if tire manufacturers agree on a common standard. The tire pressure monitoring system must detect abnormal tire pressure conditions, and it can only do so with high resolution and accuracy. Battery life is limited, and capacity is affected by temperature as well. It is best for the sensor to perform passive detection in order to improve system reliability. According to studies, the information collected by tire pressure sensors can be used to monitor vehicle suspension failures and correct navigation systems. As a result, the future automotive pressure sensor should be a passive intelligent sensor with multiple functions. Ⅴ SummaryIn recent years, automotive sensors have been the fastest growing and most widely used sensor category. The growth of the automotive industry encourages the rapid development of automotive pressure sensors. Sensor performance is improving as a result of advances in manufacturing and process technology, and tire pressure monitoring is becoming increasingly important. Ⅵ Frequently Asked Questions about Tire Pressure Sensors1.When should a tire pressure sensor be replaced?TPMS sensors are designed to last for many years.5-10 years is a likely lifespan. Given their cost, most drivers will be inclined to replace TPMS sensors on an “as needed” basis.In other words, only once their batteries have expired, or other TPMS components have failed. 2.Is it safe to drive with tire pressure sensor fault?No, driving with the TPMS Light on is not safe. It means one of your tires is underinflated or overinflated. This can cause undue wear on the tire, potentially lead to a tire failure, and cause a blowout dangerous to you and other drivers on the road. 3.How much does it cost to replace a tire pressure sensor?The average cost for TPMS sensor replacement is between $207 and $257. Labor costs are estimated between $53 and $67 while parts are priced between $154 and $190. This range does not include taxes and fees, and does not factor in your specific vehicle or unique location. Related repairs may also be needed. 4.How do you fix a tire pressure sensor?Without starting the car, turn the key to the “On” position. Press the TPMS reset button and hold it until the light blinks three times, then release it. Start the car and let it run for 20 minutes to reset the sensor. You'll usually find the tire pressure monitor reset button beneath the steering wheel. 5.How do I know if my tire pressure sensor is bad?A small light illuminates at the dashboard's display panel whenever there is a problem with the tire pressure sensors. It appears as a vivid yellow exclamation point inside of a U symbol; you'd be easily able to spot it. As soon as it turns on, the driver must check the tire for less or no air.  

CatalogⅠ IntroductionⅡ How does The Oil Pressure Sensor Work?Ⅲ Oil Pressure Sensor LocationⅣ Types of Oil Pressure Sensors4.1 Oil Pressure Switch4.2 Oil Pressure SenderⅤ How to Test an Oil Pressure Sensor?Ⅵ Symptoms of a Faulty Oil Pressure Sensor6.1 The Oil Pressure Light Blinks Over and Over6.2 The Oil Pressure Gauge Shows an Error6.3 The Oil Pressure Light Comes on Ⅶ How to Replace an Oil Pressure Sensor？ Ⅷ Conclusion Ⅸ Frequently Asked Questions about Oil Pressure SensorⅠ IntroductionOil is essential for your engine, which lubricates and reduces friction throughout the engine. Because there's no way to tell how much oil is being pumped through the engine by looking at it, your car's computer relies on the oil pressure sensor to figure it out. The oil pressure sensor is a simple electrical switch that sends data to the oil pressure gauge on the instrument cluster.  Video. How to Test an Oil Pressure Switch? Ⅱ How does The Oil Pressure Sensor Work? The primary function of an engine oil pressure sensor is to monitor the vehicle's oil pressure and communicate that data to the combination meter or instrument panel. When a problem occurs, the oil pressure sensor sends data to the car's electronic control module for analysis. The instrument cluster panel, as well as the engine oil pre-heating system, will be activated. When the oil pressure falls outside of the preset range, standard oil pressure sensors can produce a warning signal. The oil pressure sensor is made up of two parts: a spring-loaded switch and a diaphragm. The diaphragm that is exposed to oil pressure is attached to the spring-loaded switch. The pressure switch is positioned on the side of an engine block and is connected to an oil gallery. The switch spring pressure is exceeded as the oil pressure develops on the diaphragm, forcing the electrical contacts apart and causing the warning light to illuminate. If the oil pressure falls below the predetermined limit, the diaphragm releases pressure from the springs, closing the switch.Figure 1.How does The Oil Pressure Sensor work? A vehicle's dashboard can show a low oil pressure indicator light. When this light flashes constantly, any driver will recognize that the oil pressure has dropped temporarily. However, if this indication continues to illuminate, the driver will be alerted of a complete loss of oil pressure. When the engine of a vehicle is started, an electrical current flows from a fuse to the oil pressure switch, turning off the indicator light. The diaphragm pushes apart the contacts when oil pressure rises above 4.3 psi (per square inch), turning on the oil pressure light. Ⅲ Oil Pressure Sensor Location Depending on the make, model, and engine, the actual position of your oil pressure sensor may differ. Typically, the oil pressure sensor is found near the bottom of the cylinder head in the engine block. However, it can be mounted to the cylinder head as well. A block connector and one or two thin wires will be added to it.Figure 2.Location of Oil Pressure Sensors  Ⅳ Types of Oil Pressure SensorsAn oil pressure sensor is a device that measures the engine's oil pressure. The term "oil pressure sensor" refers to at least two different and unique types of sensors: an oil pressure switch and an oil pressure sender. 4.1 Oil Pressure SwitchAn oil pressure switch is a device that protects an engine. It is a specific type of oil pressure sensor. The oil pressure switch is a mechanical device with a switch within, as the name implies. The oil pressure switch can have one, two, or three pins. When most oil switches for protection are actuated to signify low oil pressure, they close. This might be done by using the engine block as a ground, or by using another approach.  Figure 3.Oil Pressure Switch 4.2 Oil Pressure SenderA form of the oil pressure sensor is an oil pressure sender. An oil pressure sender is a device that detects and sends the oil pressure of an engine to the engine or machine controller. It can be used as a generator protection device to show the user the oil pressure or for logging and diagnostic purposes. It may display a variety of readings, unlike an oil pressure switch.Figure 4. Oil Pressure Sender Ⅴ How to Test an Oil Pressure Sensor?The vehicle's gauge indicates that the engine is receiving insufficient oil pressure or that the sending unit has become faulty or damaged over time. Low oil pressure could indicate a lack of oil, which can be remedied by adding extra. It could also mean the engine is leaking oil or the system is burning it. These steps can be used to determine if the oil pressure sensor is defective. The first step is to turn the key to the accessory setting after inserting it into the ignition. Check to see if the engine is turned off and has cooled down after use. Examine the oil indicator on the dashboard after that. If the gauge is at zero, unplug the wire that is directly attached to the sending device.If the gauge keeps rising after that, the transmitter is broken and needs to be replaced. Next, connect the transmitting unit's disconnected wire to the negative part of the battery and another metal object in the vehicle.It is a good sender and does not malfunction if the oil gauge reading reads zero, which will show you whether or not the oil pressure sensor is working properly. Ⅵ Symptoms of a Faulty Oil Pressure SensorThe engine oil pressure indicator will often illuminate if there is an issue with the oil pressure sensor. It could also cause the oil pressure gauge to produce an incorrect reading. The three most common indicators of a defective oil pressure switch or sensor are listed below. 6.1 The Oil Pressure Light Blinks Over and OverThe low oil indicator on the dashboard can occasionally flicker if the oil pressure sensor is not working correctly, which could make a driver worry, leading them to feel their oil levels are low, which, if right, could damage the engine.Figure 5. Oil Pressure Light You should physically check your oil level to see whether it is low in order to establish if this is a genuine warning. If it isn't, you most likely have a malfunctioning oil pressure sensor, which you should repair as soon as possible. 6.2 The Oil Pressure Gauge Shows an ErrorIf you have an older vehicle, the oil pressure is likely calculated using a mechanical gauge. When the oil levels are normal but the gauge reads zero, it means the oil pressure sensor is broken or there is an issue with the connection.Figure 6. Oil Pressure Gauge If you drive a modern vehicle, your oil pressure gauge is almost certainly electronic, and it receives the reading via an electronic signal.In a modern car, if an oil pressure sensor fails, the gauge will display unusual readings or will remain at full or zero. Examine the sensor's wiring and replace it if necessary.Don't assume your engine oil level is low without checking the dipstick yourself. If you don't, you risk having too much oil in your engine, which can lead to a range of issues, including high oil pressure. 6.3 The Oil Pressure Light Comes onThe lights on the oil pressure gauge are the best method to see if your sensor is bad. If the low oil pressure warning light illuminates even though your engine's oil levels are normal and it runs smoothly and silently, you most likely have a faulty oil pressure sensor. This sensor will give you erroneous readings if it is malfunctioning. You have a genuine oil pressure problem if your oil levels are correct yet your engine makes grinding, ticking, or other noises, such as a malfunctioning oil pump, and the sensor is merely doing its job. These readings will eventually exceed the typical specifications, causing the warning light to illuminate. To keep track of your oil pressure level, you need to change your sensor at this point. Ⅶ How to Replace an Oil Pressure Sensor？If you notice that the oil pressure sensor is broken, you may need to look into the procedures for replacing the sensor. The oil pressure sensor, as well as the oil pressure gauge and light, can be used to notify the driver of the oiling system's state. The oil pressure may diminish as the oil degrades. The oil pressure sensor detects a drop in oil pressure and reports it to the gauge on the instrument cluster. We'll go over how to replace an oil pressure sensor step by step. To begin changing an oil pressure sensor, you'll need a screwdriver set, shop towels and rags, thread sealant, and a wrench set. Oil pressure sensors are often found in the engine block or cylinder heads. Therefore the first step is to find it. If you can't discover the sensor, consult a repair manual. Then, the electrical connector for the oil pressure sensor must be unplugged. Pull the electrical connector out of the oil pressure sensor by releasing the retaining tab. Because the oil pressure sensor is overly exposed to the elements, debris might build up over time, necessitating continuous plugging and unplugging. The oil pressure sensor must be removed as the third step. You'll need to use the wrench or socket to release the oil pressure sensor, then undo the rest by hand. Then, compare the oil pressure sensor you replaced with the one you removed. Because the oil pressure switch is installed in a place with pressurized oil, use caution. After you've completed these steps, thread the replacement oil pressure sensor into place until you can no longer turn it by hand. Reinstall the electrical connector after tightening it with the wrench or socket. The next step is to test the engine for appropriate operation by starting it and looking at the oil pressure indicator. If you do not follow these instructions, your engine may completely fail, necessitating an engine replacement. Ⅷ ConclusionThe oil pressure sensor is the most commonly used pressure transmitter in industrial practice. It is widely used in industrial automation environments involving petroleum pipelines, water conservancy, railway transportation, intelligent buildings, and many other industries. Even though the installation method is simple and the service life is long, we must have the above knowledge to get the most out of it. Ⅸ Frequently Asked Questions about Oil Pressure Sensor1. Can you drive with a bad oil pressure sensor?If the oil level is fine on the dipstick, and the engine runs quietly and smoothly, the light is most likely the result of a malfunctioning sensor. In this case, stop driving until you've resolved the issue or you could be facing major and immediate engine damage. 2. How long do oil pressure sensors last?The oil pressure sensor, like all of the other sensors and switches on a car, is designed to survive as long as the vehicle itself. Due to the wear and harsh conditions that the sensor is subjected to, this is usually not the case; the sensor will become damaged and will need to be replaced. 3. Can you clean an oil pressure sensor?If the oil level is normal, the suspect may be an oil pressure sensor. Getting the sensor replaced can't eliminate the illuminated message. It is possible to easily clean the filter screen with a brake cleaner and low air pressure. 4. How much does it cost to replace oil pressure sensor?Between $121 and $160 is the average cost for an oil pressure sensor replacement. The cost of labor is between 73 and 93 while the cost of parts is between $48 and 67. Taxes and fees are not included in the estimate. 5. Can oil leak from oil pressure sensor?A bad oil pressure switch or sender may leak engine oil. Oil leaks can be caused by several issues, so a professional inspection is order here.

IntroductionDue to their ruggedness and low cost, ultrasonic sensors are widely used in various consumer and industrial areas as an advanced and well-known technology. When adding a measuring distance or detection function to a product, an ultrasonic sensor is the ideal option. Furthermore, it has a broader applicability and improved dependability in hardware upgrades and software adaptations.Video:the Introduction of Ultrasonic SensorsCatalogIntroductionⅠ What is an Ultrasonic Sensor?Ⅱ Operating Principle of Ultrasonic SensorsⅢ Where are Ultrasonic Sensors Typically Used?Ⅳ Advantages and Disadvantages of Ultrasonic Sensors4.1 Advantages of Ultrasonic Sensors4.2 Disadvantages of Ultrasonic SensorsⅤ Limitation of Ultrasonic SensorsⅥ FAQs about Ultrasonic Sensors Ⅰ What is an Ultrasonic Sensor?An ultrasonic sensor is a type of electronic equipment that emits ultrasonic sound waves and converts the reflected sound into an electrical signal to determine the distance of a target item. Ultrasonic waves travel quicker than audible sound (i.e. the sound that humans can hear). The transmitter, which generates sound using piezoelectric crystals and the receiver, which encounters the sound after it has traveled to and from the target, are the two primary components of ultrasonic sensors.Figure:Ultrasonic Sensors Ultrasonic sensors are mostly utilized as proximity sensors. They can be found in self-parking technology and anti-collision safety systems in automobiles. In addition to robotic obstacle detection systems, ultrasonic sensors are used in manufacturing technology. Ultrasonic sensors are less susceptible to interference from smoke, gas, and other airborne particles than infrared (IR) sensors in proximity detection applications (though the physical components are still affected by variables such as heat).Ultrasonic sensors are also utilized as level sensors in closed containers to detect, monitor, and manage liquid levels such as vats in chemical factories.Most notably, ultrasonic technology has allowed the medical profession to create images of interior organs, spot malignancies, and monitor the health of newborns in the womb.Ⅱ Operating Principle of Ultrasonic SensorsUltrasonic sensors operate by emitting a sound wave at a frequency that is above the range of human hearing. To receive and transmit ultrasonic sound, the sensor's transducer functions as a microphone. Like many others, our ultrasonic sensors use a single transducer to send a pulse and receive the echo. The sensor calculates the distance to a target by measuring the time elapsed between delivering and receiving the ultrasonic pulse. This module's operation is straightforward. It emits a 40kHz ultrasonic pulse that travels through the air and, if it encounters an obstruction or object, bounces back to the sensor.The distance can be estimated by multiplying the travel time by the speed of sound.Figure:Operating Principle of Ultrasonic Sensors Ultrasonic sensors are an excellent solution for detecting clear objects. Because of target translucence, applications that use infrared sensors, for example, struggle with this particular use case for liquid level measurement.Ultrasonic sensors detect things independent of color, surface, or material for presence detection (unless the material is very soft like wool, as it would absorb sound.)Ultrasonic sensors are a trustworthy solution for detecting translucent and other things where optical methods may fail.Ⅲ Where are Ultrasonic Sensors Typically Used?Liquid level sensing is the first of the two most frequent ultrasonic sensor applications, as they can detect liquids of any hue or opacity while remaining non-contact. The second is universal object detection, which is advantageous because of its low cost and simplicity. Anti-collision detection for vehicles, person identification, presence detection, box sorting, pallet detection with forklifts, bottle counting on drink filling machines, and many other applications are examples of object detection applications.Figure:Where are Ultrasonic Sensors Typically UsedⅣ Advantages and Disadvantages of Ultrasonic Sensors4.1 Advantages of Ultrasonic Sensors1.Not affected by the color or transparency of the object Because the ultrasonic sensor reflects the sound out of the item, the color or transparency of the object does not affect the sensor's reading. 2.Can it be used in low-light conditions?Dark settings have little effect on the detecting capability of ultrasonic sensors, unlike proximity sensors that use light or cameras. 3.Unaffected by dust, filth, or high humidity levelsAlthough many sensors perform well in these situations, others generate inaccurate readings, particularly in extreme conditions when substantial volumes of dust or water build. 4.High precision in some applicationsWhen measuring the thickness and distance between parallel surfaces, ultrasonic sensors have a high degree of precision. 5.PenetrationThe ultrasonic sensor's high sensitivity and penetrating capability make it easier to detect the outside environment as well as deep things. 6.Strong anti-environmental interference:It is very resistant to environmental influence and may be used in any lighting environment. Reliable performance in a wide range of illumination settings, including indoor, outdoor, and complicated ambient light. Because ultrasonic sensors are not affected by smoke or black matter and can detect light, smoke, dust, colors, materials, and so on, they are superior to infrared sensors in various applications. 7.Wide range of applications: Ultrasonic sensors may be utilized for a variety of applications such as water level detection, drone applications, automatic obstacle avoidance applications, distance detection applications, and so on. 8.Multi-purpose: Detection of presence or absence, detection of level, detection of location, detection of distance, and so on. It can suit the needs of the majority of non-contact detecting applications. 4.2 Disadvantages of Ultrasonic Sensors• Unable to work in a vacuum.Because ultrasonic sensors rely on sound to function, they simply cannot function in a vacuum because there is no air to disperse the sound. • Unsuitable for use underwater • Soft materials will have an impact on sensing accuracy. Objects wrapped in a soft fabric absorb more sound waves, making it difficult for the sensor to see the target. • A temperature change of 5-10 degrees Celsius or higher will influence sensor accuracy.However, many manufacturers' devices now include temperature correction, and these sensors can be calibrated at starting or before each range reading based on any changes in temperature, voltage, and so on. • Small objects have a tough time reflecting sound waves.The object may be too small to reflect enough sound waves to the sensor to be detected. • It is difficult to capture the reflected wave in some shapes. Ⅴ Limitation of Ultrasonic SensorsUltrasonic sensors, such as the HC-SR04, can measure distances of up to 400 cm with a 3 mm tolerance. However, if a target object is placed in such a way that the ultrasonic signal is deflected away rather than reflected by the ultrasonic sensor, the measured distance may be wrong. In some circumstances, the target object is so small that the reflected ultrasonic signal is insufficient to identify it and the distance cannot be accurately determined.Figure:HC-SR04 Moreover, things such as fabric and carpet can absorb auditory impulses. If the signal is absorbed at the end of the target item, it cannot be reflected the sensor, and so the distance cannot be recorded. The high sensitivity of ultrasonic sensors makes them efficient, but it can also present issues. Ultrasonic sensors, for example, can identify spurious signals from airwaves disrupted by an air conditioning system and a pulse from a ceiling fan. Ultrasonic sensors can detect items within their range, but they can't tell the difference between different forms and sizes. However, by employing two sensors instead of simply one, this constraint can be circumvented. Both sensors can be installed at a distance from each other or next to each other. The shape and size of the target item can be determined by examining the overlapped shaded zone. Ⅵ FAQs about Ultrasonic SensorsHow many types of ultrasonic sensors are there?Four types.All together there are four types of ultrasonic sensors, classified by frequency and shape: the drip-proof type, high-frequency type, and open structure type (lead type and SMD type). Which ultrasonic sensor is best?First,5Pcs Ultrasonic Sensor Module Kit HC-SR04 Distance Sensor with 3pcs Mounting Bracket Compatible with Arduino UNO Mega R3 Mega2560 Duemilanove Nano Rapsberry Pi 3 Robot XBee ZigBee. Sencond,waterproof Ultrasonic Module JSN-SR04T Water Proof Integrated Distance Measuring Transducer Sensor for Arduino. How can we protect ultrasonic sensor from water?Speaker grill cloth, wire mesh, and an open-celled foam are ways to conceal ultrasonic sensors for your application.For proper operation, moisture, temperature, and acoustic return must be taken into consideration when attempting to conceal the sensor. Do ultrasonic sensors interfere with each other?A basic ultrasonic sensor will have interference in the reported range when more than one sensor is operating in the same general space.Since the sensors are not synchronized, the sensors will range at slightly different intervals. These frequency drifts cause interference between sensors for most applications. How accurate are ultrasonic sensors?The more accurate ultrasonic sensors can achieve 0.1-0.2% of the detected range under perfectly controlled conditions, and most good ultrasonic sensors can generally achieve between 1% and 3% accuracy. How far can ultrasonic sensor work?Ultrasonic sensors are suitable for close range detection up to ten meters and provide multiple range measurements per second. What is the principle of an ultrasonic sensor?Outline and detection principle. As the name indicates, ultrasonic sensors measure distance by using ultrasonic waves. The sensor head emits an ultrasonic wave and receives the wave reflected back from the target. Ultrasonic Sensors measure the distance to the target by measuring the time between the emission and reception. What is the range of ultrasonic sensors?Ultrasonic sensors are suitable for close range detection up to ten meters and provide multiple range measurements per second. What are the advantages of ultrasonic smoke detectors?Ultrasonic sensors are suitable for close range detection up to ten meters and provide multiple range measurements per second. Low power consumption – can be powered by battery, inexpensively. It can operate in many environmental conditions – ultrasonic sensors work in smoke-filled environments, where other sensors would fail. What is ultrasonic sensor in IoT?IoT ultrasonic sensors are designed for non-contact detection of solid and liquid objects. These sensors are used for a wide variety of functions from monitoring the level of water in a tank to fluid identification/concentration, to detecting object proximity. 

CatalogIntroductionⅠWhat is a MAP Sensor ?1.1 The Definition of a MAP Sensor1.2 Abbreviations for MAP sensorsⅡ How does a MAP Sensor Works？Ⅲ  The Application of a MAP Sensor on Vehicles3.1 The Problem Caused of a Faulty MAP Sensor3.2 The Factors of Causing This Fault3.3 How to RepairⅣ 7 Symptoms of a Faulty MAP SensorⅤ Common MAP Sensor Fault CodesⅥ The Difference Between MAP and MAF sensorsⅦ Frequently Asked Questions about MAP SensorsIntroductionFirstly, We need to have a general definition of a sensor. A sensor, in the broadest sense, is a device, module, machine, or subsystem whose purpose is to detect events or changes in its environment and transmit the information to other electronics, most commonly a computer processor. A sensor is always used in conjunction with other electronics.Figure1：The function of  a MAP sensorⅠWhat is a MAP Sensor ?1.1 The Definition of a MAP SensorThe manifold absolute pressure sensor (MAP sensor) is one of the sensors used in the electronic control system of an internal combustion engine.MAP sensors are frequently used in engines that inject fuel. The manifold pressure sensor transmits real-time manifold pressure data to the engine's electronic control unit (ECU). The function of data is to calculate the air density and determine the engine's air mass flow rate, determining the fuel metering required for optimal combustion and influencing the ignition timing advance or retardation. In order to detect intake airflow, fuel-injected engines may use a mass airflow sensor (MAF sensor). Aspirated engines typically use one or the other, whereas forced induction engines typically use both at the same time. The MAF sensor on the intake pipe is connected to the throttle body, and the MAP sensor on the intake port is connected to the pre-turbine.The second variable from IAT (intake air temperature sensor) can be applied to convert MAP sensor data to air quality data. It is referred to as the speed-density method. The engine speed (RPM) is also used to determine the position on the lookup table, which determines the amount of fuel to be added, and thus the speed density (engine speed/air density). The MAP sensor can also be used in OBD II (on-board diagnostics) applications to test the function of the EGR (exhaust gas recirculation) valve, which is a common application in OBD II-equipped general automobile engines.1.2 Abbreviations for MAP sensorsAbbreviations often used are:MAPThere are some other common names of MAP sensors：Manifold Absolute Pressure SensorEngine Load SensorPressure SensorBoost Sensor Ⅱ How does a MAP Sensor Works？ Its operation is based on supplying 5 volts of DC power to the sensor from the PCM (Power System Control Module). Inside the MAP sensor is a resistor that moves in response to the intake manifold pressure. The resistor alters the voltage between 1V and 4.5V (depending on engine load), and the voltage signal returns to the PCM to indicate manifold pressure (vacuum). This signal is required by the PCM to determine fuel delivery and is occasionally used to determine whether the EGR valve is functioning properly. The Manifold Pressure Sensor is useful for diagnostics because it measures throttle performance, turbo performance, and leaks in the inlet manifold. Due to its position, it should always read negative pressure unless the turbocharger is boosting pressure. This is depicted in the diagram below. Ⅲ The Application of a MAP Sensor on vehiclesA computer and a series of sensors in modern vehicles control the engine's fuel consumption and other operations. While you may never have to work on any of these sensors, one, in particular, is critical to the smooth operation of an engine — the MAP (manifold absolute pressure) sensor. What exactly is a MAP sensor and what does it do? When your engine runs strangely, it could be due to a MAP sensor failure, so let's take a look at what the MAP sensor does.Figure2: the application on vehicles  3.1 The Problem Caused of a Faulty MAP SensorA faulty MAP sensor can cause a variety of performance issues in your vehicle. If the sensor is faulty, reading too high, the fuel management system may use more fuel than necessary, reducing fuel economy. If the MAP sensor reads too low, the onboard computer will reduce the amount of fuel it believes is required and starve the engine, causing it to run erratically and produce less power. In either case, if the sensor is not properly reading, your vehicle will fail emissions testing. When you connect a diagnostic code reader, you may discover trouble codes P0068, P0069, P1106, or P1107. 3.2 The Factors of Causing This FaultA MAP sensor failure can be caused by several factors. The sensor's operation is dependent on both electronic and mechanical components. A vacuum chamber within the sensor allows the sensor to detect changes in manifold pressure. A leak in the vacuum chamber can develop over time, rendering the sensor unable to read correctly. Years of extreme temperature fluctuations and vibration can also wreak havoc on the internal circuitry due to the sensor's location in the harsh engine compartment environment. Another source of failure is dirt or other contamination that prevents the sensor from physically accessing the intake manifold air flow. 3.3 How to RepairThe difficulty of replacing a bad MAP sensor varies depending on the vehicle. It is typically bolted or screwed to the outside of the intake manifold or throttle body. Unplug the sensor wire, then unscrew the screws and carefully remove the faulty sensor. Simply reinstall the screws and plug the wire back in to get your new one up and running. Depending on the vehicle and whether or not a trouble code was set, resetting the check engine light may necessitate the use of a diagnostic tool.Many people are perplexed when they learn that they have a faulty sensor and wonder, "What is a MAP sensor?" While its function is straightforward, it has been critical to obtaining good fuel economy and performance from your vehicle's engine for many years. If you suspect a MAP sensor failure, your neighborhood NAPA Auto Care center can handle the problem and get you back on the road. Ⅳ 7 Symptoms of a Faulty MAP Sensor 1. Poor Fuel Economy.If the ECM detects low or no vacuum, it assumes the engine is under load and dumps more fuel, and advances the spark timing. This results in excessive fuel consumption, poor fuel economy, and, in extreme cases, detonation. 2. Lack of Power.When the ECM perceives a high vacuum, it assumes that the engine load is low and reduces fuel injection, and retards spark timing. On the one hand, fuel consumption will be cut down, which appears to be a good thing. However, if not enough fuel is consumed, the engine may lack acceleration and passing power. 3.Failed Emissions InspectionWhen the ECM perceives a high vacuum, it assumes that the engine load is low and reduces fuel injection, and retards spark timing. On the one hand, fuel consumption will be cut down, which appears to be a good thing. However, if not enough fuel is consumed, the engine may lack acceleration and passing power. 4. Rough Idle.Inadequate fuel injection deprives the engine of fuel, resulting in rough idling and possibly random cylinder misfiring. 5. Hard Starting.Similarly, an excessively rich or lean mixture makes it difficult to start the engine. You most likely have a MAP sensor problem if you can only start the engine when your foot is on the accelerator. 6. Hesitation or Stalling.Stepping on the gas may not be fun when starting from a stop or attempting a passing maneuver, especially if the ECM is displaying a lean mixture based on faulty MAP sensor readings. 7. Check Engine Light.MAP sensor diagnostic trouble codes (DTC) can range from a simple circuit or sensor faults to correlation or range faults, depending on the age of your vehicle. A dead MAP sensor will not read anything, whereas a failing MAP sensor may send data to the ECM that is illogical, such as low engine vacuum when the throttle position sensor (TPS) and crankshaft position sensor (CKP) both show the engine at idle.Figure3: check dash board light Ⅴ Common MAP Sensor Fault CodesThe following codes are associated with the MAP sensor and should be looked for if your check engine light has illuminated:  P0068: MAP/MAF - Throttle Position CorrelationP0069: Manifold Absolute Pressure - Barometric Pressure CorrelationP0105: MAP Circuit MalfunctionP0106: MAP/Barometric Pressure Circuit Range/Performance ProblemP0107: Manifold Absolute Pressure Figure4: one of the faulty code  Ⅵ The Difference Between MAP and MAF sensorsThe intake manifold pressure sensor is the full name of the map manifold absolute pressure sensor, and the computer uses the speed increase pressure change to adjust the speed. The following conclusions are for reference only.MAF is an air flow sensor with the full name Mass air flow meter. Figure5: the MAF sensor  The first thing I mentioned was the MAP formula, which is MAP+Manifold vacuum = Barometric Sensor. The function of the Barometric Sensor.It indicates the height of the car's altitude, allowing the length of the fuel injection to be determined when the car is cold.In general, there are two variables: the manifold vacuum and the barometric. The manifold vacuum changes with speed, while the barometric is almost constant, unless you're in the sky. 1, Manifold vacuum Full throttle (WOT) = 0 hgidle 18-22 hg2, MAp should be equal to baro in the case of KOEO (manifold vacuum is 0 hg)3, KOEO 3v-4vKOER will drop to about 1v as the vacuum increases4, 5v reference nap throttleFigure6: 5v reference nap throttle  5, KOEO 150 hz KOER will be lower than this in the future6, Reference value sunnyvale 150hz/ 30HG denver 123 hz7, if egr is stuck slightly open, map will also report an error8, The duty cycle and counts of iac will also decrease,9, stft -9% at idle accelerating jumps to lean change map. There is no absolute value, and the calibration of each car manufacturer is not the same MAF-air flow sensor, simple and rude, directly tells the computer how much flow.1, idle 0.5-1v2, egr&tps follow3, If there is another baro (calculate or extra), the method is the same as map, 30 hg4, maf is dirty, will undereportting, cause too much air to enter, fuel trim is too thin5, down side: If there is turbulence in one of the intake and exhaust, the problem cannot be determined6, maf gs/s = liter (known Toyota, Ford.)7, baro relearn( 80% tps with low rpm)Figure7: baro relearn Ⅶ Frequently Asked Questions about MAP Sensors1. Can I drive my car with a bad MAP sensor?It is not advisable to drive your vehicle with the MAP (manifold absolute pressure) sensor disconnected. ... With the MAP sensor disconnected, the fuel delivery will be excessive and could cause harm to the engine and exhaust system (catalytic converters). 2. Will a MAP sensor cause a misfire?Your engine misfires and shakes: If a MAP sensor reports a false high pressure reading, the engine's computer will signal for more fuel. This results in a rich mixture, which can foul the spark plugs and cause a cylinder not to fire. A misfiring engine will shake and transmit that motion into the cabin of the vehicle. 3. Can you clean a MAP sensor?Use an electric parts cleaner on a soft rag or paper towel to clean the outside of the MAP sensor. ... Shake out the excess and let the MAP sensor dry. Check the MAP sensor vacuum hose or intake manifold port for additional contamination. Clean these with electric parts cleaner and a brush if necessary. 4. How much is a MAP sensor?The MAP sensor usually sits in an easy to reach area, on or near the intake manifold. The sensor itself will cost you anywhere from $30 to $200, depending on your vehicle and if you use OEM or aftermarket parts. 5. Can I use alcohol to clean MAP sensor?Clean the outer surface of the MAP sensor using electric parts cleaner. ... Spray the alcohol liberally over the MAF sensor. Be sure to cover the MAF sensor's wires, intake and all its crevasses to thoroughly clean the part. Do not touch or scrub the MAF sensor's wires because they are very delicate and could break. 

CatalogⅠ What is Coolant Temperature SensorⅡ Function and Structure of Coolant Temperature SensorⅢ The Working Principle of Coolant Temperature SensorⅣ Application of Coolant Temperature Sensor in Vehicles  4.1 Location on Automobiles  4.2 Ways of Testing Coolant Temperature SensorⅤ How to Replace the Faulty Coolant Temperature  SensorⅥ Frequently Asked Questions about Coolant Temperature Sensor Analysis Ⅰ What is Coolant Temperature SensorEvery driver is aware that coolant/antifreeze is applied to keep an engine operating at peak efficiency. However, how do cooling systems recognize when the engine is at the proper operating temperature? We take a closer inspection at coolant temperature sensors in this guide, providing information on what they do and how they work, as well as step-by-step instructions for diagnosing and replacing a faulty sensor. A coolant temperature sensor (CTS) (also known as an ECT sensor or ECTS (engine coolant temperature sensor)) measures the temperature of the coolant/antifreeze mix in the cooling system, indicating how much heat the engine is producing. The sensor communicates with the vehicle's ECU and continuously monitors coolant temperature to ensure that the engine is operating at the proper temperature. Ⅱ Function and Structure of Coolant Temperature Sensor The coolant temperature sensor is installed on the water jacket of the engine block or cylinder head, contracting with the coolant directly. The CTS is applied to detect the temperature of the engine coolant. The internal part is equipped with a negative thermistor with negative temperature characteristics. The feature of a negative thermistor is that the higher the temperature, the smaller the resistance, the lower the temperature, the greater the resistance.Figure1: the circuit image of coolant temperature sensor The signal of the coolant temperature sensor is a correction signal, and its function is to inspect the temperature of the engine coolant. The temperature of the engine coolant transmit the signal to the ECU, and the ECU  measured temperature and correct the fuel injection volume according to the signal indication. When the cold car starts or the engine warms up, the ECU will correct the fuel injection.When the car is hot, the ECU will correct to inject the leaner mixture; the same way, when the engine coolant temperature signal is detected, the ECU controls the cooling and the fan is turned on and off. Ⅲ The Working Principle of Coolant Temperature Sensor Generally, the structure of the coolant temperature sensor seems to be a negative thermistor. Therefore, its temperature is inversely proportional to resistance, and its voltage is also inversely proportional to resistance. The range of temperature changes: -40 to 195°C. When the engine cools down from the start of the cold car to the hot car, the parameters of the fluid temperature sensor gradually increase, and the vehicle is idling when the engine is completely warmed up. The coolant temperature should be 85～105℃ when operating, if the parameter of CTS is  -40℃, it indicates that there is a short-circuit in CTS. If the parameter is higher than 185℃, it means that there was the same failure as-40℃. The voltage change range is 0 ~ 5V. When the temperature parameter is -40℃, the corresponding voltage is 4.98V，while the temperature parameter is 185℃, the corresponding voltage is 0.02V. The cooling system in a car with an internal combustion engine keeps the engine at the proper temperature and prevents it from overheating.  The temperature of the liquid coolant is measured by an engine coolant temperature sensor or ECT. A Negative Temperature Coefficient (NTC) thermistor is a type of engine cooling temperature sensor in which the electrical resistance decreases as the temperature rises. The ECT sensor's tip protrudes into a cooling system passage and is submerged in coolant.This vedio show that how coolant temperature sensor works Ⅳ Application of Coolant Temperature Sensor in Vehicles4.1 Location on Automobiles Many automobiles have multiple coolant temperature sensors. The primary ECT sensor (ECT sensor 1) is usually located near the thermostat in the cylinder head or block, or on the thermostat housing. Sensor for electrocardiography (ECT) the engine computer, or PCM, is connected to the ECT sensor. A second coolant temperature sensor could be installed in the radiator or in another part of the engine. Instead of or in addition to the ECT sensor, some cars use a cylinder head temperature or CHT sensor. The CHT sensor (shown in the photo) works in the same way, but it measures the temperature of the cylinder head metal rather than the coolant temperature. This enables the CHT sensor to accurately measure the temperature of the engine even when coolant is lost. This may help prevent overheating in some cases. The main computer is connected to an ECT sensor (powertrain control module or PCM). The PCM provides a constant reference voltage (typically 5 volts) and monitors the ECT sensor signal. When the temperature reaches a pre-determined level, the PCM adjusts the engine performance and operates the electric radiator fans based on this signal. If the sensor signal is missing or outside of the expected range, the PCM illuminates the Check Engine light and records the associated trouble code. 4.2 Ways of Testing Coolant Temperature SensorTesting the ECT/CHT Sensor Resistance: One method is to measure the sensor's resistance at various engine temperatures and compare the results to the service manual's specifications.We tested the resistance of the ECT sensor in this car, for example. Only when the sensor is disconnected from the circuit can the resistance be measured. The reason for this is that measuring the resistance of any electrical component that is still connected to the circuit will result in inaccurate results. When the engine was cold, the resistance was 2,953 Ohm. After the engine was fully warmed up, it dropped to 248.5 Ohm; see photo. This sensor complies with the manufacturer's specifications. Of course, the resistance specifications differ from car to car. Figure2:one way to test the resistance of senser  Checking the ECT/CHT Sensor Voltage:With the ignition on, another way to test the sensor is to measure the voltage across the sensor terminals. The voltage of the engine coolant temperature (ECT) sensor is measured. The voltage of the ECT sensor is being checked. The engine computer is linked to the sensor (PCM). The reference voltage (typically 5 volts) is supplied by the PCM, and the sensor ground is provided by another wire. The ground as well as the reference voltage must be checked first. The voltage drops as the sensor's resistance decreases as the engine warms up. We probed the ECT sensor inversely in this photo to keep it connected to the circuit. We measured 3.96 Volt when the car was cold. The voltage dropped to 0.988 Volt on a fully warmed-up engine. The multimeter will read 5 volts when the sensor is disconnected. If you don't see any voltage, the circuit is either open or shorted to the ground. One of the wires in the sensor harness, for example, could break or rub against a metal part, causing a short. Figure3: another way to test sensor Voltage  4.3  Symptoms of a bad or failing coolant temperature Poor fuel economy Poor fuel economy is one of the first signs of failure with the coolant temperature sensor. If the coolant temperature sensor fails, it can send a false signal to the computer, causing fuel and timing calculations to be thrown off. It's not uncommon for the coolant temperature sensor to fail and send a signal to the computer that's always cold. This will trick the computer into thinking the engine is cold when it isn't, causing it to consume more fuel than is necessary. The poor fuel economy will suffer as a result, and engine performance may suffer as a result. Black smoke from engine Black smoke from the vehicle's exhaust is another sign of a possible problem with the coolant temperature sensor. If the coolant temperature sensor fails and sends a cold signal to the computer, the computer may become confused and enrich the fuel mixture unnecessarily. If the fuel mixture becomes too rich, it will burn up in the exhaust pipes, resulting in black smoke. In severe cases, the black smoke may be so awful that the vehicle can not be started. Overheating engine An overheating engine is another sign of a problem with the coolant temperature sensor. The coolant temperature sensor can also fail in such a way that it sends an always-hot signal. This can cause the computer to compensate for a lean signal incorrectly, resulting in overheating, misfires, and even engine ping. Check Engine Light comes on Another sign of a problem with the coolant temperature sensor is an illuminated Check Engine Light. If the computer detects a problem with the sensor's signal or circuit in some vehicles, the Check Engine Light will illuminate. The Check Engine Light will stay illuminated until the trouble is resolved. Ⅴ How to Replace the Faulty Coolant Temperature SensorBegin with a cold engine. Drain the cooling system by jacking the car up and using jack stands. Wear safety glasses and glovesMterials:1. coolant collection pan2. flat head screwdriver3. new coolantTools:1. eyewear and golves 2. pliers3. funmel4. jack standsTip: Only do this job when the engine is completely cold and hasn't been running for at least an hour. Because you'll be underneath the car and the risk of coolant splashing in your face is high, it's a good idea to protect your face with a safety shield. If the engine is not cold, wear safety glasses and gloves to protect your hands from the hot coolant.  Step1: Locate the SensorThe CTS is usually found near the radiator or thermostat housing in the front of the engine. You may need to use a light or torch to locate it because it's a small component that's often found lower down inside the engine bay. If it's near the thermostat housing, removing the engine cover can also help you find it.Figure4: firstly, locate the coolant sensor   Step2: Remove the Connector Cable from the Terminal A connector connects the CTS to the ECU, which you must unfasten and remove. Do this with caution, as the plastic connector and wiring can be brittle and require replacement if they break. Remove the connector and place the cable somewhere out of the way.Figure5: release the connector   Step3: Loosen and Remove the Old Sensor Coolant sensors are installed similarly to spark plugs, so they must be unscrewed to be removed. Carefully loosen the sensor in an anticlockwise direction with a deep socket and ratchet, without applying too much pressure. A squirt of release spray can aid in the unsticking of stuck sensors. Remove the sensor from the socket by unscrewing it by hand once it is loose. Because coolant is likely to leak at this point, have a new one on hand or consider draining the coolant if necessary.Figure6: Remove the clip and old sensor   Step4: Install the New Sensor Clean the area with a rag or cloth to remove any dust or debris that could influence the new CTS' performance. Set the new sensor in the threads and hand-twist clockwise to ensure it is securely seated in the socket. Tighten the sensor with a torque wrench to the amount specified in the manufacturer's instructions.Figure6: install the new coolant sensor  Step5 : Reinstate the Connector Cable The only thing left to do now is reconnect the cable after the new sensor has been installed. Make sure the connector is clean and free of debris before carefully plugging it into the new sensor and tightening any clips to ensure a good connection. Start the engine to ensure the new sensor is working, and as it warms up, keep an eye on the temperature gauge on the dash to ensure the correct temperature is maintained.Figure7: reconnect the cableⅥ Frequently Asked Questions about Coolant Temperature Sensor Analysis1. Can you drive with a bad coolant sensor?It is possible to drive a vehicle with a faulty coolant temperature sensor as the management system defaults to a static reading. A vehicles coolant sensor is a critical component used by the engine management system. It directly effects, cooling and fueling of the engine and therefore effects how the engine performs. 2. What does the coolant temperature sensor do?A coolant temperature sensor (CTS) (also known as an ECT sensor or ECTS (engine coolant temperature sensor) is used to measure the temperature of the coolant/antifreeze mix in the cooling system, giving an indication of how much heat the engine is giving off. 3. What causes a coolant temperature sensor to fail?The engine may run in fail-safe mode:Many Check Engine light codes related to the (ECT) sensor; could also be caused by other reasons. Such as a bad thermostat or issues with the cooling system; including even a leaking head gasket. Therefore, The problem must be properly diagnosed. 4. How long do coolant temp sensors last?About 100,000 miles. Often, the engine coolant temperature sensor must be replaced at about 100,000 miles. If you don't properly maintain the engine cooling system, the sensor could fail much earlier. 5. Do you need to drain coolant to change coolant temperature sensor?Open the radiator valve and drain about two to three quarts of coolant. You only need to remove enough to drop the level below the sensor. Then close the drain valve. This will minimize coolant waste when you remove the sensor. 6. Can you run a car without a temperature sensor?Generally it should be ok to drive without the thermostat fitted, as it will only cause the engine to take longer to reach operating temperature. The thermostat is designed to allow the engine to reach ideal operating temperature as quickly as possible, so it would not be recommended to drive without it. 7. Can a bad coolant temp sensor cause rough idle?A faulty coolant sensor that always reads cold may cause the fuel control system to run rich, pollute and waste fuel. A coolant sensor that always reads hot may cause cold drive ability problems such as stalling, hesitation and rough idle. ... This also affects engine performance and fuel economy. 8. Does coolant temp sensor affect AC?In a properly operation system the engine coolant temperature should not affect the cooling of the air conditioner. The A/C condenser is located in front of the radiator and is first to receive the incoming airflow.