2018 Freightliner Cascadia DD15 - Forced Regen Fails and Engine Derate Stuck

Question

My truck is stuck in a 5 MPH derate and I cannot get a parked regen to complete successfully. It starts the process but kicks out after about 10 minutes with a high temperature error on the instrument cluster. I am worried about the DPF being completely face-plugged because I am seeing high soot level warnings on the dash.

Kevin Tran · Accepted Answer

The issue was the HC Doser (7th injector) was completely clogged at the manifold, which is common at this mileage. I removed the doser, cleaned the port, and replaced the injector nozzle (Part #A0004900500). After performing a forced regen using DiagnosticLink to clear the derate codes and reset the soot accumulation, the truck returned to full power. Total parts cost was around $380 and it took 2 hours of labor.

Brian O'Connor · Answer

Inspect the 7th injector (Hydrocarbon doser). If it's carboned up or the fuel line is restricted, you won't get the heat needed for the regen to sustain itself.

Rachel Nguyen · Answer

Check your Delta P sensor and the sample tubes. If those tubes are clogged with soot or if the sensor is failing, it will give the MCM a false reading and stop the regen for safety.

fleet_chief_42 · Answer

You need to look at your DOC inlet temperatures using DiagnosticLink. If the DOC isn't getting hot enough, it won't light off the DPF, and if it gets too hot too fast, it will abort to prevent a thermal event.

2018 Freightliner Cascadia DD15 - Forced Regen Fails and Engine Derate Stuck

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