Engine Coolant Temperature Sensor Circuit Low Input
Engine · Cooling System
The ECT sensor is reading extremely low resistance, which the ECU interprets as an extremely hot engine. This causes the ECU to reduce fuel delivery and may trigger cooling fans constantly, even when cold.
- Short circuit in ECT sensor wiringMost common
- Failed ECT sensor (shorted internally)Most common
- Coolant leak causing air in sensorCommon
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Frequently asked questions
What does P0117 mean?
The ECT sensor is reading extremely low resistance, which the ECU interprets as an extremely hot engine. This causes the ECU to reduce fuel delivery and may trigger cooling fans constantly, even when cold.
Is P0117 serious?
Fix promptly — engine may run rich and overheat.
How much does it cost to fix P0117?
Repair costs for P0117 range from $75 – $200 depending on the root cause and your vehicle.
Can I drive with P0117?
You can drive short distances but should have it repaired within 1-2 weeks to prevent further damage.