Code Definition

P1112 — Intake Air Temperature Sensor Circuit Intermittent Low Voltage

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: GM

About P1112

P1112 is a manufacturer-specific powertrain diagnostic trouble code recorded for GM vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1112 is stored, the module has detected a signal or supply voltage lower than the expected operating range; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1112 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The Intake Air Temperature (IAT) sensor is a negative temperature coefficient thermistor whose resistance falls as intake air warms, and the Powertrain Control Module (PCM) reads the resulting signal voltage to measure incoming air temperature for fuel and timing control. The PCM supplies a reference voltage through an internal resistor, so a hot sensor produces a low signal voltage and a cold sensor produces a high voltage. DTC P1112 sets when the PCM sees the IAT signal voltage drop intermittently to a low level, which corresponds to a momentary short to ground in the sensor or its wiring. B...

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