P0117 on a Toyota: 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 Toyota

On a Toyota, P0117 means the engine coolant temperature (ECT) sensor is reading very hot even when the engine is cold, because the signal voltage is too low. The usual causes are a failed sensor, a shorted wire, or a corroded connector. The computer may run the engine rich and turn the cooling fan on early.

Is P0117 common on Toyotas?

Higher-mileage Camrys, Corollas, and RAV4s see this code when the ECT sensor ages or its connector corrodes. It is a simple, inexpensive sensor fault, not an overheating problem, though the rich running will hurt fuel economy until it is fixed.

Commonly reported on: Camry, Corolla, RAV4, Tacoma.

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	$15–40
Repair the wiring or connector	Mechanic	$50–150
Have a shop replace the sensor and verify the circuit	Mechanic	$100–200

Frequently asked questions

Can I drive my Toyota with a P0117 code?

Yes, for a short time. The engine just runs rich and the fan may stay on, but fix it soon to save fuel.

Why does P0117 happen on Toyotas?

Because the coolant temperature sensor fails or its connector corrodes as the car ages. It is one of the more common sensor faults on higher-mileage Toyotas.

How much does a Toyota P0117 repair cost?

A coolant temperature sensor part runs about $15–$40. With a shop doing the labor, expect $100–$200.