Code
P1111
GWM
P — Powertrain
- Intake Air Temperature (IAT) Sensor High Voltage
AI status
Completed
Completed
100%
Causes
- Open or disconnected IAT sensor connector
- Short to battery/ignition feed on the IAT signal wire
- Faulty IAT sensor (thermistor out of range)
- Corroded or damaged wiring harness or pins
- Poor or missing sensor ground or reference circuit fault
- Incorrect or failed replacement sensor (wrong type)
Symptoms
- Malfunction Indicator Lamp (MIL)/Check Engine Light illuminated
- Engine runs poorly at idle or during cold start
- Poor fuel economy or increased emissions
- Delayed or rough throttle response, reduced engine performance
- Incorrect intake air temperature reading in live data (very high)
What to check
- Read and record freeze frame and stored data with a scan tool
- Verify code and check for related DTCs
- Monitor live IAT temperature and raw voltage/signal while engine is OFF and running
- Compare IAT reading to ambient temperature and another temperature source (ambient or intake air)
- Visually inspect sensor connector and wiring for corrosion, damage, or loose pins
- Backprobe the IAT signal, reference, and ground with a multimeter/oscilloscope
Signal parameters
- Typical IAT signal voltage: ~0.2–4.8 V depending on design (varies by vehicle). High-voltage fault = signal near battery voltage or above expected maximum (often >4.5 V)
- Open-circuit condition: signal may show near battery voltage or erratic values
- Typical NTC thermistor resistance at 25°C often in the kilo-ohm range (varies by sensor); resistance increases as temperature decreases for NTC sensors
- Exact voltage/resistance specs vary by model — consult GWM service data for vehicle-specific values
Diagnostic algorithm
- Connect a scan tool, note freeze frame and related codes. Confirm P1111 is current or historic.
- With ignition ON (engine OFF), monitor IAT signal voltage. A very high voltage (near battery voltage) confirms high-voltage condition.
- Compare live IAT temperature value to ambient temperature; large discrepancy supports fault.
- Visually inspect the sensor and connector for corrosion, bent pins, water ingress, or damage. Repair as needed.
- Disconnect the sensor and measure its resistance at ambient temperature; compare to factory specification or expected NTC behavior. If open or out of range, replace sensor.
- Backprobe the connector with sensor connected: verify reference (if present), signal, and ground circuits. Check for proper reference voltage or pull-up and a good ground.
- Check continuity between the sensor connector and ECM pins. Inspect for shorts to battery/ignition on the signal wire (measure between signal and battery positive) and shorts to ground.
- Repair any wiring or connector faults (clean, repair, replace harness/connector). If wiring OK and new sensor still shows high voltage, consider ECM input fault and verify with factory diagnostics.
- After repairs, clear codes, perform test drive or run readiness checks and re-scan to confirm the code does not return.
Likely causes
- Disconnected or corroded connector at IAT sensor
- Faulty IAT sensor element (open/high resistance)
- Signal wire shorted to battery voltage
- Bad ground or reference supply to sensor
Fault status
Status
IAT sensor circuit high voltage detected. ECM sees an abnormally high voltage on the intake air temperature signal circuit; may result from an open, short to battery, or faulty sensor/wiring and will set MIL.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email