Temperature Sensor 1 (Intake Air Temperature) Out of Range
The intake air temperature is outside of the expected range.
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What it means (plain English)
The truck thinks the air coming in is either too hot or too cold to be normal, which can affect performance and emissions.
What the computer is actually seeing
The ECM is reading a temperature from the intake air temperature sensor that falls outside of the normal operating range, usually below -40°C or above 125°C (-40°F to 257°F).
What a healthy reading looks like
Expected input from the IAT sensor should be between -40°C (-40°F) and 125°C (257°F) when running, with typical values around 20°C (68°F) to 30°C (86°F) on a warm day.
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.
- 1Check the wiring and connector for the intake air temperature sensor for damage or corrosion. Repair as necessary.
- 2Test the intake air temperature sensor using a multimeter; you should see variable resistance according to the temperature. A short or open will indicate a fault.
- 3If the sensor checks out, examine the intake air system for leaks or blockages; correct any issues found.
- 4If everything appears normal, clear the fault code and monitor the system for the reoccurrence of the code.
Common causes
- Damaged or corroded wiring/connector to the intake air temperature sensor
- Faulty intake air temperature sensor
- Contaminated or defective engine air filter affecting sensor readings
- Intake manifold leaks affecting air temperature readings
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
Yes, but it may affect engine performance and fuel efficiency. It's best to repair soon.
If I clear this code, will it come back?
If the underlying issue isn't fixed, likely yes.
Why does this code sometimes pair with SPN 3412?
SPN 3412 indicates issues with the turbocharger or boost pressure; improper air temperature can affect boost readings.
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