P0125

DTC P0125: Insufficient Coolant Temperature for Closed Loop Fuel Control

Wiring Diagram










DTC Detecting Condition and Trouble Area






DTC Confirmation Procedure

WARNING:

- When performing a road test, select a place where there is no traffic or possibility of a traffic accident and very careful during testing to avoid occurrence of an accident.
- Road test should be carried out with 2 persons, a driver and tester, on a level road.

NOTE:

Check to make sure that the following conditions are satisfied when using this DTC confirmation procedure.

- Intake air temp.: -14 °C, 6.8 °F or higher
- Altitude (barometric pressure): 2020 m, 6650 ft or less (540 mmHg, 72 kPa or more)

1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch and clear DTC using scan tool.
3) Start engine and drive vehicle at 40 mph (60 km/h) or higher for 20 min. or more.
4) Check DTC and pending DTC.

DTC Troubleshooting

1.
Was "Engine System Check" performed?
YES
Go to Step 2.
NO
Go to Engine System Check Engine System Check.

2. Engine coolant temp. check.

With ignition switch turned OFF, install scan tool.
Start engine and warm up to normal operating temperature with idling.
Check engine coolant temp. using scan tool.

Is engine coolant temp. less than 31 °C (88 °F)?
YES
Go to Step 3.
NO
Go to Step 10.

3. Check ECT voltage.

Disconnect connector from ECT sensor with ignition switch turned OFF.
Check proper connection to ECT sensor at "LT GRN" and "ORN" wire terminals.
If OK, then turned ON ignition switch, check voltage between "LT GRN" wire terminal in ECT sensor harness connector and vehicle body ground.






Is voltage about 4 - 6 V at each terminal?
YES
Go to Step 6.
NO
Go to Step 4.

4. Check ECM voltage.

Disconnect connectors from ECM with ignition switch turned OFF.
Remove ECM from vehicle body and connect connectors to ECM.
Check proper connection of connector at "C46-16" terminals.
If OK, then turn ON ignition switch, check voltage between "C46-12" terminal wire and vehicle body ground.

Is voltage about 4 - 6 V at each terminal?
YES
"LT GRN" wire open circuit.
If wire and connection are OK, go to Step 5.
NO
Go to Step 5.

5. Check ECM sensor harness voltage.

Disconnect connector from ECM with ignition switch turned OFF.
Turn ON ignition switch.
Check voltage between "LT GRN" wire terminal in ECT sensor harness connector and vehicle body ground.

Is voltage about 0 V at each terminal?
YES
Go to Step 6.
NO
"LT GRN" wire shorted to other circuits.
If wire are OK, substitute a known-good ECM and recheck.

6. Check ECT sensor harness resistance.

Measure resistance between "C46-12" terminal and "LT GRN" wire terminal in ECT sensor connector with ignition switch turn OFF.

Is resistance below 5 ohms?
YES
Go to Step 7.
NO
"LT GRN" wire in high resistance circuit.

7. Check ECT sensor ground circuit.

Connect connector to ECM.
Check proper connection of ECT sensor at "ORN" wire terminal.
Measure resistance between "ORN" wire terminal in ECT sensor connector and vehicle body ground.

Is resistance below 10 ohms?
YES
Go to Step 9.
NO
Go to Step 8.

8. Check ECT sensor ground circuit.

Measure resistance between "C46-27" terminal and vehicle body ground.

Is resistance below 5 ohms?
YES
"ORN" wire open circuit or high resistance circuit.
Poor "C46-27" connection.
NO
Faulty ECM ground circuit.
If circuit are OK, substitute a known-good ECM and recheck.

9. Check ECT sensor.

Check ECT sensor according to Engine Coolant Temperature (ECT) Sensor Inspection Engine Coolant Temperature (ECT) Sensor Inspection.

Is it good condition?
YES
Go to Step 10.
NO
Replace ECT sensor.

10. Thermostat Check.

Check thermostat referring to Thermostat Inspection.

Is thermostat in good condition?
YES
Substitute a known-good ECM and recheck.
NO
Replace thermostat.