Exhaust Aftertreatment Temperature Sensor 2 Fault
There’s a problem with the exhaust aftertreatment temperature sensor 2 signal.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The vehicle's computer is getting a bad reading from the sensor that measures the temperature of the exhaust aftertreatment system, which can mess with how exhaust is treated for emissions.
What the computer is actually seeing
The computer is looking for a temperature signal from the sensor that's typically around 100-800 degrees Fahrenheit while the engine is running, depending on conditions.
What a healthy reading looks like
Expected temperature reading should be between 160°F and 600°F under normal operating 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.
- 1Check the wiring and connectors going to the exhaust aftertreatment temperature sensor 2 for burns or breaks. If damaged, repair or replace as needed.
- 2Measure the voltage at the sensor connector while the engine is running; should show a consistent voltage output that changes with temperature in the expected range. If not, replace the sensor.
- 3Inspect the exhaust system for leaks or damage that could influence temperature readings. Repair if found.
Common causes
- Faulty exhaust aftertreatment temperature sensor
- Wiring issues or bad connectors in the sensor circuit
- Exhaust system leaks affecting sensor readings
Typical repair cost
$$
Related codes
Frequently asked questions
Can I drive with this code?
You can drive, but performance may be affected and emissions could be higher.
Will this code come back if I clear it?
If the cause isn't fixed, the code will likely return after some driving.
Why does this code appear with SPN 6391?
Both codes relate to exhaust temperature sensors; issues with one can affect readings in the other.
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