Engine Exhaust Temperature Sensor 1 - High
The engine exhaust temperature sensor is reading too high.
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What it means (plain English)
The computer monitors the temperature of the exhaust gases after they leave the engine. If the temperature is above normal, it triggers a warning.
What the computer is actually seeing
The engine control module (ECM) reads the sensor's voltage signal, which should range between 0.5V (cold) and 1.5V (hot). A reading above 1.5V for extended periods triggers the code.
What a healthy reading looks like
Normal exhaust temperature readings typically range from 300°F to 1300°F depending on engine load and operation. Voltage should be within 0.5V to 1.5V.
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 for any visible damage to the wiring and connectors of the exhaust temperature sensor. Repair or replace as necessary. Decision Point: If wiring is damaged, fix it and retest. If wiring is good, proceed to step 2.
- 22. Measure the voltage at the exhaust temperature sensor connector with the key on, engine off. Expected voltage is 0.5V to 1.5V. Decision Point: If voltage is outside this range, replace the sensor. If voltage is within range, proceed to step 3.
- 33. Start the engine and monitor the exhaust temperature with a scan tool. Compare readings against expected values while the engine is running. Decision Point: If exhaust temperature is excessively high compared to normal values, inspect for exhaust leaks or lean conditions before replacing the sensor. If readings are normal, investigate ECM faults.
Common causes
- Faulty exhaust temperature sensor
- Wiring or connector issues
- Exhaust leaks prior to the sensor
- High exhaust temperature due to engine lean conditions
- Faulty ECM readings
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It depends on the exhaust temperature. If you're experiencing excessive overheating or performance issues, it's best to have it checked.
Will this code come back after resetting?
If the underlying issue isn't resolved, the code is likely to return.
Why does this code sometimes pair with other SPN codes?
Multiple codes can be triggered by common issues like sensor failure or wiring problems, so it's important to diagnose the whole situation.
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