Engine Intake Air Temperature Sensor 1
The engine intake air temperature (IAT) sensor is reading out of the expected range.
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What it means (plain English)
The IAT sensor measures how hot the air going into the engine is. If it gives readings that are way too high or way too low, it means the sensor is either failed or there's an issue with the air intake.
What the computer is actually seeing
The engine control module (ECM) expects the IAT sensor to send voltages that correspond to specific temperature entries. When it sees voltages outside the expected range (e.g., below 0.5V or above 4.5V), it triggers this code.
What a healthy reading looks like
Normal IAT readings should be between -40°C and 125°C (-40°F and 257°F). Values outside this range trigger the code.
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. Check all visible wiring and connectors for the IAT sensor: Look for corrosion, pin damage, or loose connections. Decision: If any issues, repair or replace and clear code.
- 22. Inspect air intake assembly for blockages or leaks that could affect IAT readings. Decision: If found, fix and clear the code.
- 33. Use a multimeter to measure the voltage from the IAT sensor while running: You should see voltages that correspond to the air temperature. Decision: If voltage is out of range, replace the IAT sensor.
- 44. If the IAT sensor is replaced and the code returns, perform a complete ECM reset and monitor for reoccurrence. Decision: If the code comes back, test the wiring for short circuits or resistance issues.
Common causes
- Faulty IAT sensor
- Wiring issue between the IAT sensor and ECM
- Air intake obstruction
- Vacuum leaks
- ECM calibration issue
Typical repair cost
$$-$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderately drivable but you may experience poor engine performance or fuel economy. Fix soon.
Will this code come back after clearing it?
If the underlying issue isn't resolved, the code will likely return.
Why might this code appear with other codes?
It's common for sensor issues to create multiple faults if they impact engine performance.
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