What does code P0118 mean on a Honda and is it safe to drive?
P0118: Engine Coolant Temperature Circuit High Input. Here's what it means on your Honda, 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 Honda
- 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 Honda, 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 Honda
Honda P0118 on K-series and R-series engines is usually a failed ECT sensor or a broken wire at the sensor connector. Honda ECT sensors are inexpensive—check for low coolant level first, as an air bubble at the sensor can cause intermittent readings.
Most commonly affected models