Exhaust Gas Temperature 1
The exhaust gas temperature sensor 1 is reporting out of range values.
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What it means (plain English)
The exhaust gas temperature (EGT) sensor measures how hot the gases are after combustion. If the reading is too high or too low, it could mean there's a problem in the exhaust system or with the sensor itself.
What the computer is actually seeing
The engine control unit (ECU) expects the exhaust gas temperature from the sensor to stay within a specific range, usually around 300°C to 800°C (572°F to 1472°F). When it reads below 200°C (392°F) or above 1000°C (1832°F), the error code is triggered.
What a healthy reading looks like
Expected exhaust gas temperature range is approximately 300°C to 800°C (572°F to 1472°F).
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 gas temperature sensor wiring and connector for damage or corrosion. Repair as needed.
- 22. Test the voltage output from the EGT sensor with a multimeter. You should see a voltage change as the engine warms up. If there's no change, replace the sensor.
- 33. Inspect for any exhaust leaks upstream of the sensor that could affect readings. Repair any leaks found.
- 44. If the sensor and wiring are good, check the engine control unit (ECU) for correct programming and faults.
Common causes
- Faulty exhaust gas temperature sensor
- Wiring issues or bad connections to the sensor
- Exhaust leaks affecting sensor readings
- Faulty ECU programming or malfunction
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
It's best to address it soon, as it may lead to potential damage in the exhaust system or affect emissions.
Will this code come back after clearing it?
If the underlying issue isn't fixed, the code is likely to return.
Why does this code pair with SPN 640?
SPN 640 indicates high exhaust gas temperatures, which may occur along with other temperature-related faults, often due to a malfunctioning EGT sensor.
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