P0118 on a Volkswagen: Causes, Fixes & Repair Cost

🟠 Moderate severity · drivable

Safe to drive, but the engine may run rich and use more fuel until the sensor circuit is repaired.

What P0118 means on a Volkswagen

On a Volkswagen, P0118 usually points to the engine coolant temperature sensor (called G62), which sits in a plastic coolant flange on the cylinder head. A high-voltage reading means the circuit is open, either from a failed sensor, a broken wire, or a cracked coolant flange. The computer then thinks the engine is always cold and adds extra fuel.

Is P0118 common on Volkswagens?

This is a well-known VW pattern on Golf, Jetta, and Passat models. The plastic coolant flange is a common wear item that cracks and leaks, and the sensor mounted in it often fails with it, so both are usually replaced together.

Commonly reported on: Golf, Jetta, Passat, Tiguan.

Symptoms

Check engine light on
Poor fuel economy
Hard cold start
Coolant leak near the engine block

Common causes

most common: Faulty G62 coolant temperature sensor
common: Cracked or leaking coolant flange
common: Open sensor signal wire
less common: Corroded or loose connector

How to fix it

Fix	DIY?	Typical cost
Replace the coolant temperature sensor	Yes	$30–80
Replace the sensor and the coolant flange together	Yes	$80–200
Repair the sensor wiring	Mechanic	$100–250