P1285 FORD, LINCOLN, MAZDA, MERCURY: CYLINDER HEAD OVERTEMPERATURE CONDITION
POST UPDATED IN January, 2023
P1285 FORD, LINCOLN, MAZDA, MERCURY: CYLINDER HEAD OVERTEMPERATURE CONDITION
The CHT sensor (Cylinder Head Temperature) is a thermistor device whose resistance varies with temperature. This resistance decreases as the temperature increases and the resistance increases if the temperature is low. These changes in resistance directly affect the voltage drop across the terminals of the CHT sensor, which is provided to the PCM (Powertrain Control Module) as temperature information.
The Cylinder Head Temperature Sensor is located in the aluminum cylinder head and basically its function is to measure the temperature of the metal. It can send complete engine temperature information and can be used to infer the coolant temperature. In the event that the CHT sensor reports an overheat condition to the PCM, the PCM will initiate a fail-safe cooling strategy based on the sensor data.
When the DTC P1285 OBDII code is set, it is because the PCM has received information from the Cylinder Head Temperature Sensor indicating an engine overheat condition.
The factors for which the P1285 OBD2 fault code is set up are:
The corresponding steps to troubleshoot the P1285 OBDII diagnostic code are: