P0117 on a Ford: 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 Ford

On a Ford, P0117 means the engine coolant temperature (ECT) sensor is reading very hot because its circuit voltage is too low. A failed sensor or a shorted wire is the usual cause. The computer may run the engine rich and keep the cooling fan on.

Is P0117 common on Fords?

F-150s, Focuses, and Escapes see P0117 when the ECT sensor fails or the harness near the engine chafes and shorts. It is a common electrical fault that is easy to diagnose and cheap to fix.

Commonly reported on: F-150, Focus, Escape, Explorer.

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: Chafed harness near the engine
less common: Corroded or loose connector terminals

How to fix it

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