The sensor signal is high, which reads as a very cold engine. The driver may notice high consumption, black smoke or a fan running as a backup.
Likely causes, most common first
- Disconnected or open sensor
- Open wiring
- Corroded connector
- Faulty coolant temperature sensor
Parts usually involved
- Coolant temperature sensor
- Sensor connector
Test before you replace
Check the live reading, then test the connector, wiring and sensor resistance.
General guidance for generic OBD2 codes. Always follow the maker's procedure for the car in front of you.