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

Question

I am having a hell of a time getting this DD15 out of derate. The dash says SCR service required and it kicks out of a parked regen after about 10 minutes with a 'high soot load' message even though I just cleaned the filters. It feels like the system isn't getting hot enough to actually burn anything off.

Jake Morrison · Accepted Answer

The issue was a completely clogged Hydrocarbon (HC) Doser valve (Part #A0004900500) and a failed DPF Intake Temperature Sensor. The doser was carboned shut, preventing fuel from entering the exhaust stream to heat the DOC. I replaced the doser valve, replaced the sensor, and then had to run a 'DPF Ash Accumulator Reset' and 'SCR Efficiently Test' in DiagnosticLink 8.15. Once the software saw the temp hit 1100F, the derate cleared. Cost was about $450 for the doser and $120 for the sensor.

Mike Reynolds · Answer

Check your Seventh Injector (Hydrocarbon Injector) on the turbo outlet. If that nozzle is carboned up or the fuel line is Restricted, you won't get the exhaust temps high enough for the face of the DOC to light off.

torque_terry · Answer

Did you reset the ash accumulators in DiagnosticLink? If you don't tell the MCM that the filters were cleaned or replaced, it will keep the derate active because it's still calculating based on the old soot load history.

Pete Sanders · Answer

You need to look at your Delta P sensor readings. If the tubes are melted or plugged with soot, the MCM thinks the DPF is plugged even if you just put clean filters in. Check those silicone hoses for leaks.

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

Suggest a repair