P0128

P0128-COOLANT TEMPERATURE PLAUSIBILITY

For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
Engine temperature is at or below 19.9°C. With the engine running and no other ECT Sensor related DTC's present.

- Set Condition:
Engine temperature does not increase by 10°C within 5 minutes.





Diagnostic Test

1. CHECK COOLING SYSTEM PERFORMANCE

NOTE: The best way to diagnose this DTC is to allow the vehicle to remain outside overnight in order to have a completely cold soaked engine.

NOTE: Extremely cold outside ambient temperatures may cause this DTC to set.

Verify that the coolant level is correct.
Start the engine.
With the scan tool, set the engine RPM to 1500 and allow the engine to warm up for 10-15 minutes.
With the scan tool, monitor the Engine Coolant Temperature value during the warm up cycle. Make sure the transition of temperature change is smooth.
Did the engine temperature reach a minimum of 80° C (176° F)?

Yes

- Test Complete.

No

- Refer to the service information for cooling system performance diagnosis. The most probable cause is a Thermostat problem. Also, refer to any related TSBs.
- Perform the ECM Verification Test Ver. 1.Powertrain Verification Test