Sensor sobrecalentado por mal montaje o falta de flujo de aire

A temperature sensor reading the heat of the thing it is bolted to rather than the medium it is supposed to measure. It is a mounting and airflow fault, not a sensor fault, and the sensor is usually in perfect condition.

Intake air temperature is where it matters most. A sensor sited close to a hot manifold, or in a duct with little flow, reads accurately while the vehicle is moving and then climbs as soon as it stops — so the module believes the incoming air is far hotter than it is and pulls timing or enriches unnecessarily. The signature is a reading that rises when the vehicle stops and falls when it moves, which is the opposite of how ambient air behaves.

The causes are usually physical and recent. A sensor not seated to its depth, a missing insulating grommet, a heat shield left off after work, a duct rerouted, or an aftermarket intake that moved the sensor into the engine bay. Compare the reading against ambient after an overnight soak — they should agree closely, and a sensor that reads high on a cold engine has a mounting problem rather than a calibration one.