Code Definition

P1111 — Intake Air Temperature Sensor intermittent high voltage

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

About P1111

P1111 is a manufacturer-specific powertrain diagnostic trouble code recorded for Honda vehicles. 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

The Intake Air Temperature (IAT) sensor is a negative temperature coefficient thermistor that the Engine Control Module (ECM) uses to measure the temperature of air entering the engine, which it factors into fuel delivery, ignition timing, and cold start enrichment. The ECM supplies a reference voltage through an internal pull up resistor, so the signal voltage rises as the air gets colder and the sensor resistance increases. DTC P1111 sets when the ECM sees the IAT signal voltage momentarily spike above the expected range, which corresponds to an implausibly cold reading and points to an inte...

Join TaT to view the complete code information and diagnostic details.

Quick Facts