What to know about the Cylinder Head Temperature Sensor:
Your engine control module monitors and controls nearly all of your engine’s performance based on temperature measurements. During cold conditions or cold starts, the engine needs more fuel to run well and maintain a higher idle speed. When the engine is warm, less fuel is needed for the engine to operate smoothly and competently. There are a couple of methods car makers have utilized to determine engine temperature, with the most common being a coolant temperature sensor.
The coolant temperature sensor frequently monitors the engine’s heat based on the temperature of the fluid circulating in the block and reports it to the engine control module. The ECM adjusts EGR flow, engine timing and many other things based on this information. For vehicles not furnished with a coolant temperature sensor, a cylinder head temperature sensor, or CHT sensor, is employed. It comprises of two resistors encapsulated in one sensor to maintain a wide operating temperature of -40F to 260F. One resistor monitors the high temperatures and the other, the low temperatures, and reports them in a voltage reading to the ECM. From this reading, the engine control module infers the coolant temperature and bases its adjustments on it. If the CHT sensor isn’t reading correct voltages, you can experience issues ranging from long cranking times and low idle speeds on cold starts to stalling and hesitation on acceleration while the engine is warm.
Facts to Note:
The cylinder head temperature sensor doesn’t measure the coolant temperature. Rather, it measures the metal temperature and infers the coolant temperature from that.
Let the engine to cool off before servicing the cylinder head temperature sensor.
How to Fix:
The cylinder head temperature sensor is confirmed that it needs to be changed. The rubber head seal and connector are removed to access the sensor.
The faulty cylinder head temperature sensor is removed with a deep well socket to unscrew the sensor from the cylinder head.
The new cylinder head temperature sensor is installed into the head and tightened to specifications.
The electrical connection and rubber seal are reinstalled. The cylinder head temperature sensor is tested for operation with a scanner.
The vehicle is road tested to ensure proper operation of the cylinder head temperature sensor.
The CHT sensor should last the life of your vehicle. It is an electrical part and can fail suddenly, and if it does, it will need to be changed by one of your expert technicians. If you suspect you have a CHT sensor problem, have a qualified technician analyze the problem as monitoring the sensor is tricky and requires certain knowledge.
Common symptoms indicating you may need to change Cylinder Head Temperature Sensor:
Long cranking time when trying to start your engine
Trouble with accelerating
Engine stalling when at running temperature or when started cold
Idle speed when the engine is cold stays very low
Importance of this service:
The cylinder head temperature sensor can dramatically affect your engine’s performance if it is defective. It may cause running issues while you are driving in traffic including stalling and hesitation. Have it analyzed and mended as soon as possible so you don’t put yourself in a potentially difficult or dangerous driving situation.