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

Question

I am having a major headache with my Cascadia. It keeps failing the forced stationary regen at about 15 minutes in, and now the dash says I am limited to 5 MPH. The amber engine light is on and the DPF lamp is solid.

Dave Kowalski · Accepted Answer

The issue was a completely plugged Hydrocarbon (HC) Doser Injector nozzle. I removed the doser (part #A0004900500) and found it was caked in carbon. After replacing the doser valve and performing a 'DPF Ash Accumulator Reset' and 'SCR ADS Self-Check' using DiagnosticLink, the truck finally completed a full park regen. Total cost for the part was about $450 and it took 2 hours to install and prime the fuel line.

Sarah Thompson · Answer

Check the DOC inlet temperature. If the DOC is face-plugged, it can't create the heat required for the DPF to burn off the soot, causing a timeout error in Detroit DiagnosticLink.

turbo_tony · Answer

You need to look at the DPF pressure differential sensor. If the voltage isn't changing when you rev the engine, the sensor is likely dead or the tubes are melted, which causes the MCM to abort the regen for safety.

Kevin Tran · Answer

Check your outlet NOx sensor readings during the start of the regen. If the temps aren't climbing over 600 degrees fairly quickly, your 7th injector might be carboned up or the fuel block is clogged.

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

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