P0125

Wiring Diagram:

The engine coolant temperature (ECT) sensor is a thermistor located in the lower coolant passage of the engine's cylinder head. When coolant temperature is cold the sensor has a high resistance; as temperature increases the resistance of the sensor decrease. The PCM provides a five volt signal to the coolant sensor, which is also connected to PCM ground. The PCM reads the voltage drop on the signal line to determine coolant temperature.

DTC PARAMETERS
DTC P0125 will set if the coolant temperature is below 0°C (32°F) after the engine has been running for more than five minutes when no ECT and IAT DTCs have been set.

This DTC will only pass if engine start was determined to be a cold start.

IMPORTANT: The ECT signal is continuously checked when the engine is running.

DIAGNOSTIC AIDS
DTC P0125 indicates lower than normal coolant temperatures and probably does not indicate a faulty ECT subsystem.

Possible causes of low coolant temperature
^ Thermostat stuck open
^ Cooling fan always on