Code 25, Intake Air Temp Sensor CKT, High Temp Indicated: Notes

IAT sensor uses a thermistor to control signal voltage to ECM. ECM applies 4-6 volts on Red/Black wire to the sensor. When intake air is cold, sensor resistance is high. ECM will sense high signal voltage. As intake air temperature warms, sensor resistance decreases and voltage drops.

1. Simulates Code 23. If ECM stores Code 23, ECM and its wiring are okay, and IAT sensor is faulty. If Code 25 resets, IAT sensor is okay. Check for faulty wiring to ECM or a faulty ECM.