P0118 means the engine coolant temperature (ECT) sensor circuit voltage is too high, which the ECU reads as an implausibly low temperature. Because the sensor is a thermistor whose resistance rises as it cools, an open circuit or a disconnected sensor produces a high voltage that mimics extreme cold. The ECU then over-fuels for a perpetual cold start. Repair typically costs 40 to 180 EUR for a sensor or wiring fix.
DTC/P0118·Volkswagen
P0118 on Volkswagen: Causes, Symptoms and Fix Cost
Quick Answer
Moderate SeveritySafe to drive (short-term)Volkswagen
P0118 on a Volkswagen means the engine coolant temperature (ECT) sensor circuit voltage is too high, which the ECU reads as an implausibly low temperature. Because the sensor is a thermistor whose resistance rises as it cools, an open circuit or a disconnected sensor produces a high voltage that mimics extreme cold. The ECU then over-fuels for a perpetual cold start. Repair typically costs 40 to 180 EUR for a sensor or wiring fix.
Repair cost on Volkswagen€12 - €190
What does P0118 mean on a Volkswagen?
Volkswagen Golf
2005-2024VW Golf combined coolant sensors and their clips become brittle with heat cycling, so an open circuit from a cracked sensor body or a failed retaining clip is a common P0118 cause. The four-pin sensor is inexpensive and a frequent replacement item.
What causes P0118 on a Volkswagen?
Beyond the generic causes listed on the main P0118 page, these are the Volkswagen-specific patterns we see most often:
Volkswagen GolfCracked sensor body causing an open circuit
Volkswagen GolfBrittle retaining clip backing the connector out
How to diagnose P0118 on a Volkswagen with OBD2
Follow these steps to pinpoint the root cause of P0118:
- Read the code and watch the live coolant temperature PID with Skanyx. P0118 typically shows the minimum value (often around -40 C) even on a warm engine, which is a clear sign of an open circuit rather than a real cold reading
- Touch the upper radiator hose to gauge actual temperature; if the engine is hot but the PID reads -40 C, the circuit is open
- Check the sensor connector first, since a disconnected or loose plug is a frequent and easy fix; reseat it and recheck the live reading
- Inspect the connector terminals and harness for corrosion, spread pins, or a broken signal wire causing an open circuit
- Measure the sensor resistance with a multimeter; an infinite or very high reading confirms an internally open thermistor
- If the sensor and connector are good, test the signal and ground wires for continuity back to the ECU
How much does P0118 cost to fix on a Volkswagen? (EUR)
Estimated repair costs on a Volkswagen (Volkswagen costs align with the average for this code across makes).
Prices estimated as of May 2026. Costs vary by region, vehicle, and shop.
Related codes that often appear with P0118 on Volkswagen
These codes commonly cluster with P0118 on Volkswagen vehicles:
FAQ: P0118 on Volkswagen
Why does P0118 make the gauge read cold when the engine is warm?
The coolant sensor is a thermistor whose resistance rises as it gets colder, so a high signal voltage looks identical to a very cold engine. When the circuit goes open, the voltage climbs to its maximum and the ECU interprets that as extreme cold, often around -40 C, even on a hot engine.
Can I drive with P0118?
For short trips usually yes, but the ECU thinks the engine is freezing, so it over-fuels and you get black smoke and poor economy. The fan may also stay off when it is actually needed. Confirm the real temperature in live data and fix it soon so you do not miss genuine overheating.
Could a simple unplugged connector cause P0118?
Yes, and it is one of the first things to check. A loose or disconnected sensor plug creates an open circuit, which is exactly what P0118 detects. Reseat the connector, clear the code, and re-watch the live reading before assuming the sensor itself has failed.
What is the difference between P0117 and P0118?
They are opposite faults on the same circuit. P0117 is low voltage, which mimics a hot engine and usually means a short to ground or a shorted sensor. P0118 is high voltage, which mimics a cold engine and usually means an open circuit, a disconnected plug, or a failed sensor.
Looking for the full P0118 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0118 guideSkanyx · Volkswagen
Diagnosing P0118 on your Volkswagen?
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