P0125

DTC P0125 ECT Excess Time to Closed Loop Fuel CTL




Circuit Description
The VCM monitors the (ECT) sensor and Engine Run Time in order to determine how long it takes the ECT to reach the coolant temperature required for Closed Loop operation. DTC P0125 sets if the VCM determines that the ECT does not reach a minimum coolant temperature required for closed loop operation in a specified amount of time.

Conditions for Running the DTC
- The engine is running
- No active ECT sensor DTCs
- No active IAT sensor DTCs
- The IAT is greater than -40 °C (-40 °F)
- The ECT is greater than -40 °C (-40 °F)
- The start-up ECT is less than 40 °C (104 °F)
- For a vehicle with a start up coolant temperature of -40 °C (-40 °F):
- The accumulated air flow since start greater than 7,500 grams
- The accumulated idle time is less than 300 seconds
- For a vehicle with a startup coolant temperature of -7 °C (20 °F):
- The accumulated air flow since start greater than 4,500 grams
- The accumulated idle time is less than 225 seconds
- For a vehicle with a start up coolant temperature of 10 °C (50 °F):
- The accumulated air flow since start greater than 1,600 grams
- The accumulated idle time is less than 90 seconds

Conditions for Setting the DTC
The closed loop coolant temperature is not reached within a predetermined time. The maximum allowable time depends on the start-up coolant temperature and the amount of air flow into the engine.
1. For a start up coolant temperature of -40 °C (-40 °F):
The ECT is less than 20 °C (68 °F) after 8 minutes.
2. For a start up coolant temperature of -7 °C (20 °F):
The ECT is less than 20 °C (68 °F) after 5 minutes.
3. For a start up coolant temperature of 10 °C (50 °F):
The ECT is less than 20 °C (68 °F) after 2 minutes.

Action Taken When the DTC Sets
- The VCM illuminates the MIL (Malfunction Indicator Lamp) if a failure is detected during 2 consecutive key cycles.
- The VCM will set the DTC and records the operating conditions at the time the diagnostic fails. The VCM stores the failure information in the scan tools Freeze Frame and/or the Failure Records.

Conditions for Clearing the MIL/DTC
- The VCM turns OFF the MIL after 3 consecutive drive trips when the test has Run and Passed.
- A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 22 °C (40 °F) from the startup coolant temperature and the engine coolant temperature is more than 70 °C (158 °F) during the same ignition cycle).
- Use the scan tool Clear Information function.

Diagnostic Aids
When a DTC P0125 sets, an out of range ECT sensor, a low ECT sensor signal from the VCM, or the engine thermostat that does not operate correctly is indicated.

An intermittent may be caused by any of the following conditions:
- A poor connection
- Rubbed through wire insulation
- A broken wire inside the insulation

Thoroughly check any circuitry that is suspected of causing the intermittent complaint. Refer to Intermittents and Poor Connections Diagnosis.

If a repair is necessary, then refer to Wiring Repairs or Connector Repairs.

Steps 1 - 2:

Steps 3 - 6:

Steps 7 - 12:

Steps 13 - 14:

Test Description
The numbers below refer to the step numbers in the diagnostic table.
4. This test checks the engine warm-up rate. In the Conditions for Setting the DTC text, the technician should be able to reference the allowable engine run time relative to the cold start up temperature of the vehicle.
5. This test checks the coolant sensor reading on the scan tool and the actual coolant temperature.