The P0115 code indicates that the engine control module has detected a malfunction in the Engine Coolant Temperature (ECT) sensor 1 circuit. This typically means the sensor is providing an improbable voltage signal or the circuit has been interrupted.
The sensor has developed an internal short or open circuit, preventing it from sending an accurate temperature signal.
Frayed, broken, or shorted wires in the sensor harness can interrupt the signal to the PCM.
Corrosion or moisture inside the sensor plug increases resistance and distorts the voltage reading.
Insufficient coolant can leave the sensor tip dry, resulting in inaccurate temperature readings.
An internal failure within the engine control module's processing circuit for the ECT input.
It is risky because the PCM may not be able to accurately manage engine temperature or fuel mixtures, which can lead to overheating or engine damage.
No. While some may suggest replacing the PCM, this is extremely rare; the vast majority of P0115 cases are caused by the sensor itself or the wiring.
Not necessarily. If the root cause is a broken wire or a corroded connector, a new sensor will not resolve the issue.