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

Question

My truck is stuck in a 5 MPH derate and every time I try to run a parked regeneration, it aborts after about 10 minutes. The dash is showing a 'High Soot Level' warning and the data link seems to drop out right before the cycle fails. I can hear the 7th injector clicking but the exhaust temps don't seem to get over 600 degrees.

turbo_tony · Accepted Answer

The issue was a completely plugged Hydrocarbon Doser Fuel Line (the small hard line) and a faulty DOC Inlet Temperature Sensor that was reading 150 degrees off. I replaced the DOC Inlet Sensor (A0009058403) and cleared the hard line with shop air and brake clean. After performing an 'Aftertreatment Device Regeneration' and a 'DPF Ash Accumulator Reset' using DiagnosticLink, the truck completed a full 45-minute regen and the derate cleared. Total parts cost was about $240 and 3 hours of labor.

Sarah Thompson · Answer

Pull the Hydrocarbon Doser block and check the fuel line supply. Sometimes the internal screen in the block gets silver flakes from a failing high-pressure pump, which starves the 7th injector even if the injector itself is new.

dieselmike88 · Answer

You need to look at your MCM/ACM software versions. There was a service bulletin for 2018 models where the temperature thresholds were too tight, causing the regen to abort if it didn't hit 800 degrees fast enough.

Ashley Park · Answer

Check your Delta P sensor and the tubes leading to it. If those tubes are clogged with soot, the MCM won't see the pressure change it expects during the burn and will kill the process for safety.

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

Suggest a repair