P0125

Circuit Description

This diagnostic test monitors the Engine Coolant Temperature sensor after a timer has reached 4.25 minutes. The PCM looks at the test conditions every second, and increments the timer each time the test conditions are met. After the timer has reached 4.25 minutes, if ECT is less than or drops below 5°C (41°F) for 3 seconds, DTC P0125 will be set. If ECT is greater than 5°C (41°F), the test will be considered passed regardless of the timer. The timer will be decremental if the PCM is disabling fuel to any cylinder during traction control maneuvers, acceleration reduction, torque management, etc. The timer will reset only when the engine stops running.

Conditions for Running the DTC

^ DTCs 112, 113, 117 or 118 not set.
^ Engine running.
^ Intake air temperature 0°C (32°F) or more.
^ Vehicle speed at least 10 MPH.

Conditions for Setting the DTC

At least 4.25 minutes have passed since test conditions were met and engine coolant temperature is less than 5°C (41°F) for 3 seconds.

^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
^ The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records.

Conditions for Clearing the MIL/DTC

^ The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.
^ A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail.
^ A History DTC will clear after forty consecutive warm-up cycles with no failures of any emission related diagnostic test.
^ Use a scan tool to clear DTCs.
^ Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended.

Diagnostic Aids

If fault is not present check for an intermittent cooling system problem.
Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

2. Checking DTC P0125 snapshot for the ECT sensor reading at the time the DTC set.
3. Checking for a faulty ECT sensor. If the reading is erratic, the sensor may be faulty.
4. Checking if vehicle can reach normal operating temperature.
5. Checking for a cause of high resistance that would cause a low sensor reading. If CKT's are okay problem must be vehicles ability to reach normal operating temperature, possible stuck open thermostat.
6. Checking for poor terminal contact at the ECT sensor.