Engine Exhaust Temperature (EET) Sensor 1 Fail
Exhaust temperature sensor for cylinder 1 is out of range or failed.
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What it means (plain English)
The engine has a sensor that measures the temperature of the exhaust coming from cylinder 1, and it's either not working or showing a temperature that doesn't make sense.
What the computer is actually seeing
The computer monitors the temperature readings from the exhaust sensor. If it reads a value that is too high (above 900°F) or too low (below 150°F), or if there's no reading at all, it triggers this code.
What a healthy reading looks like
Normal exhaust temperature for a diesel engine should range between 300°F to 800°F during operation, depending on load and engine 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. Inspect the wiring and connectors for the exhaust temperature sensor. Check for corrosion, damage, or loose connections. Decision: If damaged, repair or replace. If okay, proceed to step 2.
- 22. Measure the voltage at the exhaust temperature sensor with the engine running. Expected voltage is typically between 0.5V and 4.5V depending on temperature. Decision: If out of range, replace the sensor. If within range, proceed to step 3.
- 33. Using a scan tool, monitor live data for the exhaust temperature sensor. Check if the readings respond when the engine warms up. Decision: If readings are flat or erratic, replace the sensor. If readings respond accurately, further diagnose ECM or wiring.
Common causes
- Defective exhaust temperature sensor
- Wiring harness issues or shorts
- Poor connection at the sensor or connectors
- Faulty engine control module (ECM)
- Excessive exhaust leaks leading to inaccurate readings
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's generally safe to drive, but you may experience performance issues, and it's advisable to fix it soon.
Will this problem come back after repair?
If the cause is correctly identified and fixed, it should not come back.
Why do I see this code with other SPNs?
This code often appears with other exhaust temperature issues or sensor codes, indicating potential related problems.
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