DTC 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 for system information. | ||
| Application | Key On Engine Off | Key On Engine Running | Continuous Memory |
| Vehicles with only a cylinder head temperature (CHT) sensor | - | - | GO to DL: Cylinder Head Temperature (CHT) Sensor STEP DL21. |
| Vehicles with only an engine coolant temperature (ECT) sensor | - | - | GO to DX: Engine Coolant Temperature (ECT) Sensor STEP DX18. |
| Vehicles with both a CHT and an ECT sensor | - | - | GO to DX: Engine Coolant Temperature (ECT) Sensor STEP DX18. |