P0117 Engine Coolant Temperature Circuit Low
The ECT sensor reports an unrealistically hot reading (low voltage).
Common causes
- Shorted sensor or wiring
- Faulty sensor
Symptoms
- Check engine light
- Fan runs constantly
- Hard cold starts
What to check
- Check reading on a cold engine
- Inspect for shorts to ground
Manufacturers may add their own detail to generic codes. If your vehicle shows a different description for P0117, follow the service information for that make and model.