DTC P1112 - IAT SENSOR CIRCUIT INTERMITTENT LOW 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 VSS DTCs set.
2. Vehicle speed at least 2 MPH.
3. Engine running longer than 100 seconds.
4. IAT sensor voltage less than 0.82 volt.