DTC P0128: Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2005 Mercury Sable, 2005 Mercury Mountaineer, 2005 Mercury Monterey, 2005 Mercury Montego, and 2005 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.
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. |