High Exhaust System Temperature
The exhaust temperature is higher than expected at the exhaust aftertreatment system.
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What it means (plain English)
The exhaust system’s temperature readings are too high, which can happen due to engine issues or problems with the exhaust components.
What the computer is actually seeing
The engine control module (ECM) receives temperature data from the exhaust temperature sensor and compares it to set parameters. If the temperature exceeds these parameters, the ECM triggers a fault code.
What a healthy reading looks like
Normal exhaust temperature during operation is typically between 300°F and 1200°F depending on engine load and conditions.
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 the exhaust temperature sensor connector for damage or corrosion. (Decision: If yes, repair/replace the connector; if no, proceed.)
- 22. Measure the resistance of the exhaust temperature sensor with a multimeter. Compare to manufacturer specifications (usually around 2-3 ohms at room temp). (Decision: If out of spec, replace the sensor; if in spec, proceed.)
- 33. Inspect the exhaust system for blockages or restrictions. Check for signs of soot or damage in the piping. (Decision: If blockage found, clear it; if no blockage, proceed.)
- 44. Monitor exhaust temperature with a scan tool while running the engine to see actual values under load. (Decision: If the temperature exceeds 1200°F, further diagnostics of engine performance may be needed; if not, clear the code and test drive.)
Common causes
- Failed exhaust temperature sensor
- Faulty wiring or connectors at the exhaust temperature sensor
- Excessive exhaust back pressure
- Contamination or restriction in the exhaust system
- Engine running lean or rich causing higher temperatures
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
No, it's not safe to drive if the exhaust temperature is too high; it can cause damage to the engine and exhaust components.
Will this issue come back after replacing the sensor?
If there are underlying issues causing high exhaust temperatures, it could return. Be sure to diagnose fully before replacing.
Why does this code appear with low coolant?
Low coolant can cause the engine to overheat, which raises exhaust temperatures and can trigger this code.
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