Engine Coolant Temperature Sensor Circuit High
Engine · Cooling System
The ECT sensor is reporting an open circuit (maximum resistance), which the ECU interprets as an extremely cold engine. Commands a rich fuel mixture indefinitely, causing poor fuel economy and potential catalytic converter damage.
- Failed coolant temperature sensorMost common
- Open circuit in wiring harnessCommon
- Low coolant levelLess common
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Frequently asked questions
What does P0118 mean?
The ECT sensor is reporting an open circuit (maximum resistance), which the ECU interprets as an extremely cold engine. Commands a rich fuel mixture indefinitely, causing poor fuel economy and potential catalytic converter damage.
Is P0118 serious?
Fix promptly — engine may run rich and overheat.
How much does it cost to fix P0118?
Repair costs for P0118 range from $75 – $200 depending on the root cause and your vehicle.
Can I drive with P0118?
You can drive short distances but should have it repaired within 1-2 weeks to prevent further damage.