Engine Exhaust Temperature Sensor 1 Out of Range
The temperature reading from the exhaust temperature sensor 1 is outside the expected range.
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What it means (plain English)
The exhaust temperature sensor 1 is supposed to read between specific temperatures but is reporting values that are too low or too high for normal operation.
What the computer is actually seeing
The engine control unit (ECU) receives readings from the exhaust temperature sensor that are significantly above 1,200°F (649°C) or below 300°F (149°C), indicating a fault.
What a healthy reading looks like
Exhaust temperature sensor readings should typically be between 300°F (149°C) and 1,200°F (649°C) under normal operation.
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 exhaust temperature sensor wiring and connectors for damage or corrosion. Fix any issues found. Decision: If wiring is okay, go to step 2. If damaged, repair or replace as needed.
- 22. Measure the voltage at the exhaust temperature sensor connector with the key on and engine off. You should see a voltage between 0.5V to 4.5V. Decision: If voltage is out of range, replace the sensor. If within range, go to step 3.
- 33. Start the engine and take exhaust temperature readings. Use an infrared temp gun to compare actual exhaust temps at the sensor location to the values reported by the ECU. Decision: If there’s a large discrepancy, the sensor is likely defective. If readings match, investigate possible ECU issues.
Common causes
- Faulty exhaust temperature sensor
- Exhaust leaks causing incorrect readings
- Wiring issues like shorts or breaks
- Faulty connector to the sensor
- ECU calibration issues
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's best to fix it soon to avoid potential engine damage or emissions issues.
Will this code come back after clearing?
If the underlying issue isn't fixed, it will likely return.
Why does this code pair with other SPN codes?
It often indicates overall exhaust temperature system issues, which can trigger multiple related codes.
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