P0128: Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
WARNING: This page does not describe the selected car, but rather 30 other vehicles, including the 2004 Mercury Sable, 2004 Mercury Mountaineer, 2004 Mercury Monterey, 2004 Mercury Marauder, and 2004 Mercury Grand Marquis. 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 , 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. |