The Quick Answer above is the generic definition. What follows is what is documented for the Volkswagen models that log P0115, checked against manufacturer data and owner reports.
DTC/P0115·Volkswagen
P0115 on Volkswagen: Causes, Symptoms and Fix Cost
Quick Answer
Moderate SeveritySafe to drive (short-term)Volkswagen
P0115 on a Volkswagen means the ECU has detected a general fault in the engine coolant temperature (ECT) sensor circuit. The ECT sensor is a thermistor whose resistance changes with temperature, telling the ECU how warm the coolant is so it can adjust fuelling, ignition timing and the cooling fan. A fault here usually points to a failed sensor, damaged wiring or a bad connector. Repair typically costs 40 to 180 EUR depending on whether you DIY or use a shop.
Repair cost on Volkswagen€12 - €180
Connect any standard Bluetooth OBD2 adapter to your Volkswagen and Skanyx tells you what P0115 means on that engine, whether it is safe to keep driving, and what the fix should cost. Free on iPhone and Android.
Get Skanyx freeWhat does P0115 mean on a Volkswagen?
Volkswagen Golf
2005-2024Many VW Golf models use a combined coolant temperature sensor with a known weak point: the plastic sensor body and its retaining clip become brittle with heat cycling and can crack, causing intermittent readings or coolant seepage. The four-pin black or green sensor is a common replacement item.
What causes P0115 on a Volkswagen?
Beyond the generic causes listed on the main P0115 page, these are the documented Volkswagen-specific patterns:
Volkswagen GolfCracked plastic sensor body on the combined coolant sensor
Volkswagen GolfBrittle retaining clip causing an intermittent connection
How to diagnose P0115 on a Volkswagen with OBD2
Follow these steps to pinpoint the root cause of P0115:
- Read the code and watch the live coolant temperature PID with Skanyx. On a cold engine it should read close to ambient air temperature, then climb steadily to around 85 to 95 C as the engine warms
- If the live value is stuck at a fixed default (often -40 C or 120 C/maximum), that points to an open or shorted circuit rather than a true temperature reading
- Inspect the ECT sensor connector for corrosion, bent pins, or a loose fit, and check the wiring for chafing or rodent damage
- Measure the sensor resistance with a multimeter and compare against the manufacturer resistance-versus-temperature table
- Check coolant level, because a low level can leave the sensor tip in air and skew the reading
- If the sensor and wiring test good but the fault persists, check the sensor ground and signal continuity back to the ECU
How much does P0115 cost to fix on a Volkswagen? (EUR)
Estimated repair costs for P0115 in EUR, compiled across makes. Volkswagen costs typically sit in the middle of each range.
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
Related codes that often appear with P0115 on Volkswagen
These codes commonly cluster with P0115 on Volkswagen vehicles:
Looking for the full P0115 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0115 guideSkanyx · Volkswagen
Diagnose P0115 on your Volkswagen
Your car logged P0115. Skanyx reads it on any standard Bluetooth OBD2 adapter, tells you whether it is safe to keep driving, and shows the €12-€180 repair range so you know the number before a shop quotes you. Free on iPhone and Android, and you do not need to be a mechanic to read it.
Get Skanyx free