DTC P1112 - IAT SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE Oldsmobile Cutlass VI

Note. For circuit reference, see the appropriate WIRING DIAGRAMS article. For connector and terminal identification, see CONNECTOR IDENTIFICATION .

Circuit Description

Intake Air Temperature (IAT) sensor is a thermistor. PCM applies and reads a 5-volt reference signal to sensor. When air is cold, sensor resistance is high and PCM will measure a high signal voltage. If air is warm, sensor resistance is low causing PCM to measure low voltage.

Conditions required to set DTC are

1. No ECT, MAF, or VSS sensor DTCs set.
2. Engine running longer than 10 seconds.
3. Vehicle speed greater than 25 MPH.
4. IAT signal voltage intermittently indicates IAT greater than 274°F (134°C).
5. IAT sensor voltage intermittently less than 0.14 volt.