Intake Air Temperature Sensor 2
The system is detecting an issue with the second intake air temperature sensor.
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What it means (plain English)
Your engine computer has a second sensor for measuring how hot the air entering the engine is. If that sensor is not working right, it can't tell the engine how to mix air and fuel properly.
What the computer is actually seeing
The computer expects a voltage signal from the intake air temperature sensor, typically between 0.5V (representing -40°C) and 4.5V (representing 125°C). If the voltage is outside this range or does not change as expected with temperature, it will trigger the error code.
What a healthy reading looks like
Voltage should be between 0.5V and 4.5V, ideally rising as temperatures increase from -40°C to 125°C.
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 for damage or corrosion. Repair as needed. Decision point: Are connections intact? If yes, proceed to step 2. If no, repair or replace connections.
- 22. Check the values from both intake air temperature sensors using a scan tool. Decision point: Is SPN 3839 correlating with sensor 1 values? If yes, suspect a faulty second sensor. If not, proceed to step 3.
- 33. Test the intake air temperature sensor 2 with a multimeter. Expect a voltage between 0.5V and 4.5V at various temperatures (just start the engine and monitor the changes). Decision point: Is the voltage within range? If yes, suspect ECM issue. If no, replace the faulty sensor.
Common causes
- Faulty intake air temperature sensor
- Wiring or connector issues
- ECM (Engine Control Module) problems
- Corrosion at connection points
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's best not to drive long distances, as it can affect engine performance and fuel economy.
Will this code come back after clearing?
If the underlying issue is not resolved, yes, it will likely return.
Why do I see this code along with SPN 3838?
SPN 3838 relates to the first intake air temperature sensor; issues in both may indicate a shared wiring or connection problem.
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