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

Question

My DD15 is stuck in a severe derate and I can't get a parked regen to complete. Every time I initiate the process through the dash, it runs for about 10 minutes and then kicks out with a 'Regen Aborted' message. I am currently stuck at a rest area and need to get this moving before the tow bill kills me.

Tom Patel · Accepted Answer

Found the issue: the Hydrocarbon Doser Block (injector) was completely failed internally and wasn't spraying any fuel into the exhaust, despite being clean on the outside. Replaced the HC Doser (Part #A0004900500) and performed a 'Service Regeneration' using Detroit Diagnostic Link 8.1. The regen finally stayed lit, temps hit 1100F, and the derate cleared. Total cost was about $450 for the part and 2 hours of labor.

Sam Holloway · Answer

You need to look at your Exhaust Temperature Sensors, specifically the ones before and after the DPF. If the engine doesn't see at least 600-700 degrees Fahrenheit within the first few minutes of the HC doser firing, it assumes a hardware failure and kills the regen.

dieselmike88 · Answer

Check your Delta P sensor (DPF Pressure Interface Sensor) and the metal tubes leading to it. If those tubes are clogged with soot or if the sensor is failing, the MCM won't see the pressure drop it expects during the burn and will abort the cycle for safety.

Brian O'Connor · Answer

Verify your DOC inlet temperatures. If your DOC is face-plugged or the hydrocarbon doser valve itself is failing to pulse fuel into the exhaust stream, you won't get the heat necessary to cook the soot out of the DPF.

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

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