Faulty coolant temperature sensor. Corroded or damaged connector. Wiring open or short circuit. Low coolant level exposing sensor. Thermostat fault causing incorrect readings.

Which cars are affected by P0115?

P0115 is most commonly reported on Peugeot, Renault, Vauxhall, Ford, Volkswagen vehicles, but can appear on any make.

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P0115

Medium severity

Engine Coolant Temperature Sensor Circuit

The engine coolant temperature (ECT) sensor circuit is sending a signal outside the expected range. This sensor is critical for fuel mixture, ignition timing, and fan control.

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Common causes of P0115

1Faulty coolant temperature sensor

2Corroded or damaged connector

3Wiring open or short circuit

+2 more causes

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Commonly affected vehicles

PeugeotRenaultVauxhallFordVolkswagen

P0115 can appear on any vehicle — these are the makes where it is most frequently reported.

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Recalls & technical bulletins

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Related fault codes

P0171Medium

System Too Lean (Bank 1)

P0300High

Random/Multiple Cylinder Misfire Detected

P0420Medium

Catalyst System Efficiency Below Threshold (Bank 1)

P0172Medium

System Too Rich (Bank 1)