Code 25, Intake Air Temp Sensor Circuit High Temp Indicated

IAT sensor uses a thermistor to control signal voltage to ECM. ECM applies 4-6 volts on Gray wire to sensor. When manifold air is cold, sensor resistance is high. ECM will sense high signal voltage. As air temperature warms, sensor resistance will reduce, and voltage will drop.

NOTE: Test numbers refer to test numbers on diagnostic chart.

Code 25 will set if signal voltage indicates air temperature greater than 277°F (136°C) for 2.7 seconds.
If resistance is out of specification, replace IAT sensor.