P0128: Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
P0128 - COOLANT THERMOSTAT (COOLANT TEMPERATURE BELOW THERMOSTAT REGULATING TEMPERATURE)
| Description: | Indicates that the thermostat monitor has not achieved the required engine operating temperature within a specified amount of time after starting the engine. | ||
| Possible Causes: |
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| Diagnostic Aids: | Refer to THERMOSTAT MONITOR , Description and Operation, for system information. | ||
| Application | Key On Engine Off | Key On Engine Running | Continuous Memory |
| Vehicles with a CHT sensor only | - | - | GO to PINPOINT TEST DL: CYLINDER HEAD TEMPERATURE (CHT) SENSOR Step 22. |
| Vehicles with an ECT sensor only | - | - | GO to PINPOINT TEST DX: ENGINE COOLANT TEMPERATURE (ECT) SENSOR Step 18. |
| Vehicles with both CHT and ECT sensor | - | - | GO to PINPOINT TEST DX: ENGINE COOLANT TEMPERATURE (ECT) SENSOR Step 18. |