P0115 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.
DTC/P0115·Ford
P0115 on Ford: Causes, Symptoms and Fix Cost
Quick Answer
Moderate SeveritySafe to drive (short-term)Ford
P0115 on a Ford 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 Ford€11 - €171
What does P0115 mean on a Ford?
Ford Focus
2005-2024The Ford Focus coolant temperature sensor is straightforward to replace on most petrol and diesel variants. Wiring and connector issues near the engine harness are a common root cause, so inspect the pigtail for heat damage before assuming the sensor itself has failed.
What causes P0115 on a Ford?
Beyond the generic causes listed on the main P0115 page, these are the Ford-specific patterns we see most often:
Ford FocusHeat-damaged connector or pigtail near the engine harness
Ford FocusThermistor drift causing implausible cold-start readings
How to diagnose P0115 on a Ford 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 Ford? (EUR)
Estimated repair costs on a Ford (Ford parts and labour typically run 5% below the average for this code).
Prices estimated as of May 2026. Costs vary by region, vehicle, and shop.
Related codes that often appear with P0115 on Ford
These codes commonly cluster with P0115 on Ford vehicles:
FAQ: P0115 on Ford
Can I drive with a P0115 code?
For short trips, usually yes. The engine runs on a default temperature value, so you may get worse fuel economy and rough cold starts. The bigger risk is that the temperature gauge may be wrong, so you lose your warning for genuine overheating. Fix it soon and watch the temperature in the meantime.
How much does it cost to fix P0115?
The sensor itself is cheap, usually 12 to 45 EUR, and replacement is a simple job on most engines. A DIY fix can be under 50 EUR. A shop replacement runs roughly 60 to 150 EUR, and tracing a wiring fault costs more because of the labour involved.
Where is the engine coolant temperature sensor located?
It is usually threaded into the cylinder head, thermostat housing, or a coolant passage near the top of the engine, so its tip sits in the coolant. Many engines have two sensors, one for the ECU and one for the dash gauge. Check a vehicle-specific guide for the exact spot.
Is P0115 the same as a thermostat problem?
No. P0115 is an electrical fault in the temperature sensor circuit, not a cooling problem. A stuck thermostat is more likely to set P0128 (coolant below thermostat regulating temperature). They can feel similar from the gauge, so confirm with live data before buying parts.
Looking for the full P0115 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0115 guideSkanyx · Ford
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