P0117 on a Lexus: Causes, Fixes & Repair Cost

🟠 Moderate severity · drivable

Safe to drive, but the engine may run rich and the fans may stay on until the sensor circuit is repaired.

What P0117 means on a Lexus

On a Lexus, P0117 means the engine coolant temperature (ECT) sensor is sending a low-voltage signal that the computer reads as the engine being very hot. The sensor sits in the coolant flow near the thermostat, and a shorted sensor or wiring is the typical cause. Lexus engines use the same reliable Toyota-style ECT sensor, which rarely fails on its own.

Is P0117 common on Lexuss?

P0117 is uncommon on Lexus models like the ES, RX, and GX because the ECT sensors are durable. When it does appear, it is usually on higher-mileage cars where wiring or the connector was disturbed during other service work.

Commonly reported on: ES, RX, GS, GX.

Symptoms

Check engine light on
Cooling fans running constantly
Poor fuel economy
Temperature gauge reading high with a cool engine

Common causes

most common: Faulty coolant temperature sensor
common: Sensor signal wire shorted to ground
common: Corroded or loose connector
less common: Wiring damaged during previous repairs

How to fix it

Fix	DIY?	Typical cost
Replace the coolant temperature sensor	Yes	$30–80
Repair the sensor wiring or connector	Mechanic	$60–150
Have a shop diagnose the circuit	Mechanic	$80–120

Frequently asked questions

Can I drive my Lexus with a P0117 code?

Yes. The code means the sensor reads hot, not that the engine is overheating. Confirm the real coolant temperature and fix the sensor soon.

Why does P0117 happen on Lexus models?

The ECT sensor itself can fail, but on Lexus the wiring or connector is often disturbed during other repairs because the sensors are normally durable.

How much does it cost to fix P0117 on a Lexus?

A replacement sensor is about $30 to $80, plus labor if a shop does it. Wiring repairs run about $60 to $150.