What are the common causes of P0117?

Shorted engine coolant temperature (ECT) sensor. Shorted ECT sensor signal wire to ground. Faulty coolant temperature sensor. PCM fault. Contaminated coolant making the sensor read incorrectly.

Inspect the ECT sensor wiring and connector for shorts or damage. Read live ECT temperature on an OBD-II scanner and compare to a known-good value. Test the sensor's resistance with the engine cold and warm. Repair any shorted wiring. Replace the ECT sensor if resistance out of specification.

P0117

Engine Coolant Temperature Circuit Low Input

System: Fuel and air metering (P code)
Lamp: Check Engine Light
Category: Powertrain - Fuel/Air Metering

What it means

P0117 means Engine Coolant Temperature Circuit Low Input.

Check these first

Shorted engine coolant temperature (ECT) sensor
Shorted ECT sensor signal wire to ground
Faulty coolant temperature sensor
PCM fault
Contaminated coolant making the sensor read incorrectly

What to do next

Inspect the ECT sensor wiring and connector for shorts or damage
Read live ECT temperature on an OBD-II scanner and compare to a known-good value
Test the sensor's resistance with the engine cold and warm
Repair any shorted wiring
Replace the ECT sensor if resistance out of specification

Look up another code

Code or symptom

Enter a full code or a symptom. Press / to search. How to read a code

Type a code above, or start from a symptom or a common code.

Updated

Generic SAE J2012 definition. Last updated 2026-08-30.