P1290 FORD, LINCOLN, MAZDA, MERCURY: CYLINDER HEAD TEMPERATURE SENSOR SIGNAL BELOW SELF-TEST RANGE
POST UPDATED IN January, 2023
P1290 FORD, LINCOLN, MAZDA, MERCURY: CYLINDER HEAD TEMPERATURE SENSOR SIGNAL BELOW SELF-TEST RANGE
The CHT (Cylinder Head Temperature) is a sensor located in the cylinder head, not connected to a coolant line. This device provides a voltage signal to the PCM (Powertrain Control Module), which informs it about the actual cylinder head temperature.
When the temperature detected by the CHT Sensor is higher than 126 ° C, the PCM prevents the operation of 4 fuel injectors at the same time. The PCM alternates the four disabled injectors every 32 engine cycles. The cylinders that are prevented from receiving fuel injection function as air pumps and through this help to lower engine temperatures. In the event that the temperature exceeds 154°C, the PCM proceeds to deactivate the fuel injectors until the engine temperature is lowered below 154°C.
The P1290 OBDII fault code is set on Ford, Lincoln, Mazda, and Mercury vehicles when, after performing various self-tests, the PCM detects that the cylinder head temperature is below the expected values.
P1290 OBD2 diagnostic code is set for one of the following reasons:
The steps to follow to troubleshoot the DTC P1290 OBDII code are as follows: