What does code P0118 mean and is it safe to drive?
P0118: Engine Coolant Temperature Circuit High Input. Here’s what it means, what usually causes it, what repairs typically cost, and how urgent it is to keep driving.
PowertrainGenerally safe to drive
Repair cost
$50–$200
System
Powertrain
Urgency
medium
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
- 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
Repairs for P0118 often fall between $50 and $200, depending on the cause and your vehicle.