Possible Causes
- The engine control module measured a signal voltage above a specified range but not necessarily a short circuit to power, gain too high
- Blockage in coolant system
- Insufficient mixture of antifreeze creating possibility of icing in coolant system
- Connector is disconnected, connector pin is backed out, connector pin corrosion
- Engine coolant temperature sensor circuit short circuit to power, short circuit to ground, open circuit, high resistance
- Engine coolant temperature sensor failure