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

Question

I am struggling with a constant derate on my Cascadia. The dash says 'Service Regen Required' but every time I try to run a parked regen it gets about 10 minutes in and then just kicks out with a 'Regen Interrupted' message. I can't get over 5 miles per hour and I'm losing money sitting at this truck stop.

backyard_bart · Accepted Answer

The issue was a completely failed Hydrocarbon Doser (7th Injector) and a cracked doser block fuel line. The doser was internally restricted and wasn't atomizing fuel into the exhaust stream, so the DOC never reached the required 600 degrees to start the soot burn. Replaced the Doser Valve (A0004900500) and the fuel supply line, then performed a 'DPF Ash Accumulator Reset' and a service regen via DDDL. Total parts cost was around $650 and it's pulling fine now.

turbo_tony · Answer

Check the EGR valve. If it's stuck slightly open, it will dump too much soot during the warmup phase and the computer will kill the regen process to protect the filters.

Dave Kowalski · Answer

Hook up Detroit Diesel Diagnostic Link (DDDL) and look at the 'Regen Entry Conditions'. It usually tells you exactly why it aborted, like a coolant temp sensor being out of range or a faulty DPF pressure sensor.

Tom Patel · Answer

You need to check your DOC inlet temperatures during those first 10 minutes. If the temp isn't climbing fast enough, the MCM will abort the regen to prevent face-plugging the DPF. Check the Hydrocarbon Doser fuel line for clogs.

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

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