Active Exhaust Aftertreatment System Deactivation
The exhaust aftertreatment system is deactivated.
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 computer's monitoring the aftertreatment system, usually used to clean exhaust, but it's not working as it should and shut off to prevent damage.
What the computer is actually seeing
The engine control module (ECM) detects that the aftertreatment system is not operating because it's not meeting required performance metrics, signaling a fault.
What a healthy reading looks like
Expected pressures in the aftertreatment system should be between 2-5 psi during active regeneration; temperatures should be above 600°F for effective 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. Check visual condition of the exhaust aftertreatment system components for any obvious damage or leaks. Decision: Is there visible damage? If yes, repair the damage.
- 22. Inspect wiring and connectors associated with the temperature sensor and other aftertreatment components. Decision: Are all connections tight and free from corrosion? If not, repair as needed.
- 33. Verify the DEF levels and quality in the tank, ensuring it's at least above the minimum fill level. Decision: Is DEF present and not contaminated? If no, refill with the correct DEF.
- 44. Use a scan tool to check for related fault codes. Decision: Any additional codes present? If yes, diagnose accompanying codes as they may contribute to the issue.
- 55. Conduct a vacuum pressure test of the DPF. Expected value should be below 3 psi. Decision: Is the DPF pressure within the expected values? If not, it may need cleaning or replacement.
Common causes
- Faulty temperature sensor
- Clogged DPF (Diesel Particulate Filter)
- Bad wiring or connectors to the aftertreatment system
- Incorrect fluid levels or type for diesel exhaust fluid (DEF)
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Not recommended; driving can lead to further damage to the aftertreatment system.
Can this issue come back after repairs?
Yes, if the underlying problem isn't fixed, it can recur.
Why does this code relate to multiple aftertreatment codes?
These components are interconnected; one failure can affect the readings and operation of the others.
Working a real vehicle right now?
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