2018 Freightliner Cascadia DD15 - Forced Regen Fails and Stuck in 5 MPH Derate

Question

My DD15 is stuck in a 5 MPH derate and I cannot get a parked regen to complete. Every time I initiate the process through the dash or my diagnostic tool, it runs for about 10 minutes and then shuts down with a 'Regen Aborted - Low Exhaust Temp' message. I need to get this truck moving before my clock runs out.

Carlos Diaz · Accepted Answer

The issue was a completely plugged Hydrocarbon (HC) Doser injector (part number A0004901013). I removed the doser and found the tip carboned over, preventing fuel from entering the exhaust stream to light off the DOC. After replacing the HC Doser and the fuel line leading to it, I performed a 'Service Recovery Regen' using Diagnostic Link. The temps hit the required 1100 degrees, the soot level dropped to zero, and the derate cleared. Total cost for the part was around $380 plus two hours of labor.

turbo_tony · Answer

Have you checked your 7th injector (Hydrocarbon Dosers)? If that fuel injector is clogged or the fuel block is gummed up, you won't get the spray needed to raise the DOC temps high enough for the DPF to burn off the soot.

Brian O'Connor · Answer

Look at your intake throttle valve operation. If the valve isn't closing slightly to help build heat during the cycle, the exhaust won't get hot enough. Also, check for any charge air cooler leaks that might be cooling the combustion too much.

Dave Kowalski · Answer

Hook up Detroit Diagnostic Link and check the 'DOC Inlet Temp' vs 'DPF Inlet Temp' while the regen starts. If the DOC temp doesn't jump up quickly once the dosing starts, your hydrocarbon primary line might be restricted.

2018 Freightliner Cascadia DD15 - Forced Regen Fails and Stuck in 5 MPH Derate

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