DTC P1111 - IAT SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE GMC Envoy I

Note. For circuit reference, see WIRING DIAGRAMS - 4.3L article.

Circuit Description

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

Conditions for setting DTC

1. No ECT, VSS, MAF sensor DTCs not set.
2. Vehicle speed less than 2 MPH.
3. ECT greater than 183.2°F (84°C).
4. IAT greater than -34.6°F (-37°C).
5. Engine run time greater than 100 seconds.