For 1990-2009 cars

The intake air temperature (IAT) sensor is a thermistor that varies resistance according to changes in air induction temperature. The powertrain control module (PCM) supplies a 5-volt reference through a pull-up resistor to the sensor, which is connected to ground. When the sensor is cold it has high resistance (high signal voltage at PCM). As the sensor temperature increases, its resistance decreases (lower signal voltage at PCM). The PCM uses the signal voltage to determine air induction temperature. DTC P0112 sets when the IAT sensor signal voltage at the PCM is below the calibrated voltage value (over the calibrated temperature value).

### DTC Parameters

DTC P0112 will set if IAT sensor temperature is over 125°C (257°F) when:

• | The condition exists for longer than 20 seconds.

• | The ignition is ON.

DTC P0112 diagnostic runs continuously when ignition is ON.

DTC P0112 is a type A DTC.

### Diagnostic Aids

To locate an intermittent problem, use a scan tool to monitor IAT temperature with ignition ON, engine OFF. Wiggling the wires while watching for a change in IAT temperature may locate the area where a short to ground in the wiring could lie.

Refer Engine Controls Component Descriptions for a Temperature versus Resistance chart.