Engine Exhaust Temperature Sensor 1
Fault detected in exhaust temperature sensor circuit.
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 engine's computer thinks the sensor measuring the exhaust temperature is sending out bad data or is broken.
What the computer is actually seeing
The Engine Control Module (ECM) sees inconsistent or out-of-range voltage signals from the exhaust temperature sensor. Normally, a functioning sensor sends 0.5-4.5 volts depending on the temperature being measured.
What a healthy reading looks like
Expected voltage from the exhaust temperature sensor should be between 0.5V (low temp) and 4.5V (high temp).
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 the wiring and connectors to the exhaust temperature sensor for signs of damage or loose connections. Decision: Are the connections secure and undamaged? Yes - Proceed. No - Repair/replace as needed.
- 22. Measure the voltage at the exhaust temperature sensor connector with the engine running. Decision: Is the voltage within 0.5V to 4.5V? Yes - Move to step 4. No - Replace the sensor.
- 33. If the sensor is faulty, replace it and clear the fault codes. Decision: Did the fault code return? Yes - Check wiring continuity. No - Job done.
- 44. If the readings are normal and the code still returns, inspect for exhaust leaks near the sensor. Decision: Are there any exhaust leaks? Yes - Repair the leak. No - Consider ECM faults.
Common causes
- Wiring harness damage or loose connections
- Faulty exhaust temperature sensor
- Exhaust leaks affecting sensor readings
Typical repair cost
$$
Related codes
Frequently asked questions
Can I still drive the vehicle with this code?
Yes, but expect possible reduced performance and increased emissions. Fix it soon.
Will this code come back after clearing it?
If the underlying issue isn't resolved, yes, it will likely return.
Why do I see this code with SPN 380?
Both SPN codes relate to exhaust temperature inputs; issues with the sensor setup often affect multiple readings.
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 →