DTC P1111 - IAT SENSOR CIRCUIT INTERMITTENT HIGH 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 3 minutes.
3. Vehicle speed less than 35 MPH.
4. MAF less than 12 grams per second.
5. ECT greater than 140°F (60°C).
6. IAT signal voltage intermittently indicates IAT less than -29°F (-34°C).