What does code P0118 mean on a Chevrolet and is it safe to drive?
P0118: Engine Coolant Temperature Circuit High Input. Here's what it means on your Chevrolet, what usually causes it, what repairs typically cost, and how safe it is to keep driving.
What this code means
The engine coolant temperature (ECT) sensor is reporting a voltage signal that is too high, which the PCM interprets as an extremely cold or open-circuit condition. This is opposite to P0117 (low input) and often means the sensor or its wiring has failed open.
Common causes for your Chevrolet
- Failed engine coolant temperature sensor
- Open circuit in ECT sensor wiring
- Corroded or damaged sensor connector
- Low coolant level exposing the sensor
Symptoms
- Check Engine Light
- Engine runs rich (PCM thinks it is always cold)
- Poor fuel economy
- Hard starting when warm
Typical fixes
- Replace engine coolant temperature sensor
- Inspect and repair wiring and connector
- Check coolant level
Repair cost range
For a Chevrolet, repairs for P0118 often fall between $50 and $200, depending on the cause and whether you use OEM or aftermarket parts. Labor rates vary by location.
Known issues on Chevrolet
GM P0118 on Ecotec 2.4L and 1.4T engines typically means a failed ECT sensor or a wiring harness connector issue. The sensor on Ecotec engines is near the thermostat housing and is accessible; inspect the harness connector for corrosion.
Most commonly affected models