2018 Freightliner Cascadia DD15 - Forced Regen Fails and Logged Derate 520222 14

Question

My truck is stuck in a 5 MPH derate and every time I try to run a parked regen it gets about 10 minutes in and then just kicks out with a 'Regen Aborted' message. I can hear the 7th injector clicking but the exhaust temperatures don't seem to climb high enough to burn anything off. I'm worried the DPF is too plugged or the DOC is face-plugged.

Rachel Nguyen · Accepted Answer

The issue turned out to be a restricted Hydrocarbon (HC) Doser block and a faulty fuel pressure sensor at the doser valve. I replaced the HC Doser (part #A0001401539) and performed a low-pressure fuel system bleed. After clearing the codes with DiagnosticLink 8.x and performing an 'Aftertreatment Device Regeneration' and a 'SCR ADS Self-Test', the truck successfully completed a full 45-minute regen and the derate was lifted. Total parts cost was around $450.

Pete Sanders · Answer

Have you checked the Hydrocarbon (HC) doser fuel line? If the line is kinked or the block is clogged, the 7th injector won't spray enough fuel to light off the DOC, which is why your temps aren't rising.

Tom Patel · Answer

Run a relative compression test using DiagnosticLink to make sure you don't have a dead cylinder dumping raw oil into the DPF. Also, check the intake throttle valve operation; if it's not closing to increase load, you'll never hit the 600+ degrees needed.

Kevin Tran · Answer

It sounds like a failed DOC. If the face of the Diesel Oxidation Catalyst is covered in soot or coolant from a previous EGR leak, it can't catalyze the fuel into heat. You might need to pull the 'one-box' and inspect the inlet side.

2018 Freightliner Cascadia DD15 - Forced Regen Fails and Logged Derate 520222 14

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