For a complete wiring diagram Refer to Section 8W.
Ignition on, Engine running, and no ECT DTCs present.
PCM recognizes that the ECT has failed its self coherence test. The coolant temp should only change at a certain rate, if this rate is too slow or too fast this fault will set. Two trip fault. Three good trips to clear MIL. The MIL and ETC light will illuminate.
|
Possible Causes
|
|
LOW COOLANT LEVEL |
|
(K2) ECT SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE |
|
(K2) ECT SIGNAL CIRCUIT OPEN |
|
(K900) SENSOR GROUND CIRCUIT OPEN |
|
(K2) ECT SIGNAL CIRCUIT SHORTED TO GROUND |
|
(K2) ECT SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT |
|
THERMOSTAT |
|
ECT SENSOR |
|
PCM |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
NOTE: If this code sets during extreme ambient temperatures, improper installation of a block heater could be the cause of this DTC.
NOTE: If an Engine Coolant Temperature (ECT) DTC is set along with this code, diagnose the ECT DTC first.
NOTE: Inspect the ECT terminals and related PCM terminals. Ensure the terminals are free from corrosion and damage.
NOTE: The best way to diagnose this DTC is to allow the vehicle to sit overnight outside in order to have a totally cold soaked engine.
NOTE: Extremely cold outside ambient temperatures may have caused this DTC to set.
NOTE: Need to make sure that no Cooling System DTCs are set or changes that would make the warm up much slower or much faster: broken water pump can set this, addition of aftermarket auxiliary cooler can set this DTC.
WARNING: Never open the cooling system when the engine is hot. The system is under pressure. Failure to follow these instructions can result in personal injury or death. Allow the engine to cool before opening the cooling system.
NOTE: This test works best if performed on a cold engine (cold soak).
NOTE: If engine coolant temperature is above 82 degrees C (180 degrees F), allow the engine to cool until 65 degrees C (150 degrees F) is reached.
NOTE: As the engine warms up to operating temperature, the actual coolant temperature (thermometer reading) and the Eng Coolant Tmp Deg on the scan tool should stay relatively close to each other.
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.