Code Definition

P1111 — Intake Air Temperature (IAT) Sensor Circuit Intermittent High Voltage

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

About P1111

P1111 is a manufacturer-specific powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1111 is stored, the module has detected a signal or supply voltage higher 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.

P1111 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

This code is set when the powertrain control module (PCM) detects an intermittent high-voltage signal from the Intake Air Temperature (IAT) sensor. The IAT sensor provides a voltage signal based on air temperature; as temperature increases, resistance decreases, lowering the voltage. A high voltage reading suggests a wiring fault, sensor malfunction, or poor electrical connection.

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