Engine Inlet Temperature Sensor 1 - Voltage Above Normal
The engine inlet temperature sensor is reporting a high voltage.
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What it means (plain English)
The sensor that measures the temperature of air entering the engine is sending a voltage signal that’s too high—over 4.5 volts, indicating a possible short to power or a faulty sensor.
What the computer is actually seeing
The engine control module (ECM) expects the temperature sensor to output a voltage typically between 0.5V to 4.5V, based on air temperature. If it reads above that, it triggers the SPN 3380 code.
What a healthy reading looks like
0.5V to 4.5V is the normal operating range for the sensor based on intake air temperature.
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.
- 1Verify that the ignition is on and the engine is off. Check the inlet temperature sensor wiring for frays or damage. Look for signs of corrosion or loose connections.
- 2With a multimeter, measure the voltage at the sensor connector. If it reads above 4.5V, there’s likely a short or faulty wiring.
- 3Test continuity from the sensor connector back to the ECM. If there's no continuity or there's a short to power, repair the wiring accordingly.
- 4If the wiring checks out, replace the engine inlet temperature sensor. Clear the codes and retest. If the code resets, consider checking the ECM.
Common causes
- Faulty engine inlet temperature sensor
- Wiring short to battery positive
- Bad connectors or corrosion at the sensor
- ECM failure
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's drivable, but check it soon. Performance may be impacted.
Will the code come back after clearing it?
Yes, if the underlying issue isn't fixed, it will return.
Why does this code sometimes pair with other SPN codes?
It can occur alongside codes related to other intake or temperature issues, indicating a systemic problem.
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