Inlet Air Temp Sensor Circuit High
The inlet air temperature sensor voltage is above the normal range.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The inlet air temperature sensor is measuring a voltage that's too high, indicating that the air temperature is higher than it should be under normal operating conditions.
What the computer is actually seeing
The Engine Control Unit (ECU) sees a voltage signal from the inlet air temperature sensor that exceeds the normal operating range, typically above 4.9 volts or below 0.5 volts.
What a healthy reading looks like
Inlet air temperature readings should be between 0°C to 40°C (32°F to 104°F) and the sensor output voltage should be between 0.5V to 4.5V.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect wiring and connectors to the inlet air temperature sensor for damage or corrosion. Are they intact? If no, repair or replace as needed.
- 22. Check the inlet air temperature sensor voltage with your multimeter. Is it above 4.5V or below 0.5V? If yes, replace the sensor.
- 33. Test the sensor by applying heat (from a heat gun) and observing voltage change. Does it vary properly with temperature? If no, replace the sensor.
- 44. Check for a short circuit in the wiring using a multimeter in continuity mode. Is there continuity where there shouldn’t be? If yes, repair the wiring.
- 55. Verify grounds in the system. Are the grounds good? If no, repair the grounding point.
Common causes
- Faulty inlet air temperature sensor
- Short circuit in the wiring harness
- Ground issues in the sensor circuit
- High intake air temperature due to environmental conditions
- ECU programming errors
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Moderate severity means you can drive, but it's best to fix soon due to potential performance impact.
Will this problem come back after fixing?
If you repair the wiring or replace the faulty sensor, it shouldn't return unless there's another issue.
Why does this code pair with SPN 3982?
SPN 3982 relates to the same sensor but indicates a low voltage issue, often seen together due to electrical faults.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →