When a Forced Regen Won't Complete: Cleaning a Face-Plugged DPF on a PACCAR MX-13

If a parked or forced regen keeps failing and you're seeing low power with high exhaust temps, the DPF is almost certainly plugged with ash — not just soot — and no amount of regen will fix it. A regen burns off soot, but ash doesn't burn. Once the filter face is packed, backpressure stays high, the regen aborts, and the truck derates. The only real fix is pulling the DPF and cleaning it. That's exactly what we did on a 2019 Kenworth T880 with a PACCAR MX-13 at a North Lincoln fleet yard.