P0117 on a Honda: Causes, Fixes & Repair Cost

🟠 Moderate severity · drivable

Safe to drive for a short time, but the engine may run rich and burn extra fuel, and the cooling fan may run constantly.

What P0117 means on a Honda

On a Honda, P0117 means the engine coolant temperature sensor (called the TW sensor on many Hondas) is reading full hot because the signal voltage is too low. The usual causes are a failed sensor or a wiring short. The computer may run the engine rich and keep the radiator fan running.

Is P0117 common on Hondas?

Civics, Accords, and CR-Vs commonly throw P0117 as they age, usually from the sensor failing or its connector corroding. The sensor is cheap, easy to reach, and quick to replace, so this is one of the simpler fixes on the brand.

Commonly reported on: Civic, Accord, CR-V, Odyssey.

Symptoms

Check engine light on
Cooling fan runs constantly
Poor fuel economy from rich running
Hard starting when the engine is cold

Common causes

most common: Faulty coolant temperature sensor
common: Sensor wiring shorted to ground
common: Corroded or loose connector terminals
less common: Damaged wiring harness near the sensor

How to fix it

Fix	DIY?	Typical cost
Replace the coolant temperature sensor	Yes	$15–45
Repair the wiring or connector	Mechanic	$50–150
Have a shop replace the sensor and verify the circuit	Mechanic	$100–210