P0117 Code: Engine Coolant Temperature Circuit Low Input

🟠 Moderate severity · drivable

Drivable, but the computer may think the engine is hotter than it is, causing poor warm-up running.

What P0117 means

The engine coolant temperature (ECT) sensor is reading very hot (low voltage), usually because the circuit is shorted or the sensor is faulty. The computer may think the engine is overheating when it isn't.

Symptoms

Check engine light is on
Cooling fans may run constantly
Poor fuel economy
Temperature gauge reading wrong

Common causes

most common: Faulty engine coolant temperature sensor (shorted)
common: Shorted wiring in the ECT circuit
less common: Corroded sensor connector

How to fix it

Fix	DIY?	Typical cost
Replace the engine coolant temperature sensor	Yes	$30–100
Repair shorted ECT wiring	Mechanic	$50–150

Frequently asked questions

Can I drive with a P0117 code?

Yes, but the computer's wrong reading can hurt warm-up running and fuel economy. Fix it soon.

What is the most common cause of P0117?

A faulty coolant temperature sensor that has internally shorted.

How much does it cost to fix a P0117?

Typically $30–$100 for a new coolant temperature sensor.

Related codes

P0116

P0116 Code: Engine Coolant Temperature Sensor Range/Performance

P0118

P0118 Code: Engine Coolant Temperature Circuit High Input

P0115

P0115 Code: Engine Coolant Temperature Circuit Malfunction

P0117 by vehicle brand

Causes and repair costs for P0117 differ between makes. Pick your brand for the specifics.

P0117 on a Mercedes-Benz

Volkswagen

P0117 on a Volkswagen

Updated 2026-08. This page is informational and not a substitute for professional diagnosis.