Engine Exhaust Temperature Sensor 1
Indicates a fault with the first exhaust temperature sensor in the system.
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What it means (plain English)
The engine control module (ECM) monitors the temperature of the exhaust gases to optimize performance; if it detects incorrect readings, it triggers this code.
What the computer is actually seeing
The ECM sees voltage or resistance levels from the exhaust temperature sensor that are out of the expected range. Typically, a sensor should output between 0.5V (low temp) to 4.5V (high temp) based on the exhaust temperature, which ranges from about 100°C (212°F) to 800°C (1472°F).
What a healthy reading looks like
Expect output voltage between 0.5V and 4.5V corresponding to exhaust temps from 100°C to 800°C; values outside this range indicate a fault.
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 exhaust temperature sensor wiring and connectors for damage or corrosion. If found, repair or replace.
- 22. Measure the voltage output of the exhaust temperature sensor while the engine is running. If it’s outside the expected range (0.5V to 4.5V), proceed to the next step.
- 33. Check for exhaust leaks near the sensor. Repair any leaks found.
- 44. If wiring and sensor output are okay, consider testing or replacing the exhaust temperature sensor.
- 55. Clear the code and retest. If it comes back, the ECM may need testing.
Common causes
- Faulty exhaust temperature sensor
- Wiring issues or damaged connectors
- Exhaust leaks affecting readings
- ECM malfunction
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's generally drivable, but fix it soon to avoid potential performance issues.
Will the code come back if I clear it?
Yes, if the underlying issue is not fixed, the code will likely return.
Why does this code sometimes pair with SPN 2412?
SPN 2412 indicates a similar issue with the second exhaust temperature sensor, often seen together due to related faults.
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