Active Regeneration Incomplete
The engine's exhaust aftertreatment system regeneration did not complete successfully.
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 engine tries to clean the DPF by burning off soot, but it didn't finish the process.
What the computer is actually seeing
The engine control module registers an incomplete regeneration event when the DPF (Diesel Particulate Filter) cleaning process doesn’t reach the necessary temperature or conditions for completion.
What a healthy reading looks like
DPF temperature during active regeneration should be around 600°F to 900°F (315°C to 482°C) and pressure differentials should be within normal limits (less than 5 inHg) during this process.
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 DPF temperature sensor for proper operation. Hook up a scan tool and monitor the temperature readings. Expected operation is between 600°F and 900°F during regeneration. If readings are out of range, replace the sensor.
- 22. Inspect the DPF for blockage. Use a pressure gauge to measure the differential pressure; it should be under 5 inHg. If pressure is high, clean or replace the DPF as necessary.
- 33. Verify fuel quality. Ensure the correct fuel is being used and that there are no injection issues. Check for signs of poor combustion or black smoke.
- 44. Check for exhaust leaks before and after the DPF. Use a smoke machine or visual inspections. Any leaks found in the exhaust can affect regeneration effectiveness.
- 55. Inspect the air intake system for restrictions. Ensure the air filter is clean and check for any blockage in hoses.
Common causes
- Faulty DPF temperature sensor
- Clogged DPF filter
- Insufficient fuel quality or injector issues
- Exhaust leaks
- Air intake restrictions
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It’s not recommended to drive long distances without resolving the issue, as it may lead to increased emissions and potential engine damage.
Will the code come back after clearing it?
If the underlying issue isn’t fixed, the code will likely return after clearing it.
Why does this code often pair with SPN 2802?
SPN 2802 also relates to regeneration issues, indicating that multiple sensors or system components may be affected.
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