Driving along a narrow canyon road in a big rig, in a one way construction zone with a line of traffic behind you, with no pullouts available…what is the last thing you want to see? A blinking red message on your dash, in all caps, that says STOP ENGINE, with a large exclamation point for added emphasis. That was our fate two days ago, driving on US 50 between Montrose and Gunnison, Colorado. We were just 23 miles from our destination, the Gunnison KOA.
The last thing you want to see is the red STOP ENGINE!
To be fair, just before this STOP ENGINE message, literally 3 minutes before, while still driving in the one way construction zone with no pullouts, we got a yellow check engine message with a DPF lamp blinking. Definitely something I wanted to stop and check on, but where? This is important, because Freightliner says what happened next is not covered under warranty and is my fault. We continue driving until we find a pullout, which was shortly after the STOP ENGINE message, perhaps 1 mile.
“Check Engine!” on our New Aire dash
Of course we have no internet (Verizon phone indicated 1X), so we rely on the Freightliner manual which says a manual or “parked” regen is required to clear particulates from the DPF (diesel particulate filter). OK, a little odd. With over 100,000 miles driving on the newer EPA engines with DPF we’ve never needed a manual regen, but whatever. So we follow the somewhat obtuse instructions to force a manual regen and nothing happens. The RPMs are supposed to increase for 20-60 minutes and burn off the particulates. But that didn’t happen. We repeated the process several times and still nothing. So it’s time to call Freightliner.
The technician answered within 5 minutes and translated my 6 faults codes, which are not in plain English because that would be too easy. Here is one example code, “SPN: 3251 FMI: 0 OC: 1 SA: 0”. Helpful. All 6 codes were about the same thing, the diesel particulate filter was clogged and I needed to force a regen. Right, but I already tried that. Here comes the fun part. Once the STOP ENGINE message is displayed, you can’t force a regen. A Cummins technician with a laptop and Cummins proprietary software is required to clear the STOP ENGINE message before starting the regen. The closest such technician is in Grand Junction, 124 miles away. Would Freightliner pay for that technician to come here? No. Would they pay to tow our RV to the closet Cummins dealer? No. Wait, I’m still under the 3 year Freightliner warranty, what gives?
Fault codes display on your dash using the “Diagnostics” option in your menu scroll, here are the first three. Make sure you scroll down for more, we had 6 fault messages
At least we were stranded with scenic views
Here’s the rub. Remember that brief period, no more than 3 minutes, where I had the check engine light and DPF lamp blinking, before the STOP ENGINE message? And there was nowhere to pull off due to the narrow road and construction zone? Freightliner says that was my chance to stop and force a regen. Since I continued driving it’s my fault and they are not covering anything. Not wanting to fight about who is paying for what but wanting to continue our trip, we called the Cummins service center (Transwest of Grand Junction) directly and paid for a mobile service guy to drive 3 hours (each way) and get us running again. The cost for this? $1570.
The Transwest technician used a computer to clear the stop engine and force a regen cycle
The Cummins certified tech was great and deals with this exact problem all the time. He said that here in Western Colorado, with all the mountains and steep curves, regen rarely occurs passively and forced regen is common. The key being can you pull over during the short period before check engine becomes STOP ENGINE. Passive regen, the most common type of regen, happens when you’re driving on the highway and you never even know it’s occurring. Here’s some very interesting info the tech gave me on passive regen: you have to drive at least 45 mph for 45 minutes for the regen to occur. Well, that explains why it never occurred for us. The last time we were on a long, flat highway was in Santa Fe, NM. We had driven hundreds of miles on small, winding, steep roads since then, never hitting the required 45/45 combo. And the harder an engine works, such as climbing steep grades on the Million Dollar Highway, the sooner a regen is needed.
The moral of the story is that Freightliner should display an approximate count down of when regen will be required. Also, we should be able force a regen after the dreaded STOP ENGINE message occurs. Research reveals a scanner that displays the last time a regen occurred and an approximate count down of when the next one needs to occur. Cheap insurance for $150. I just ordered one.
Update: We thought this was resolved with the mobile service, but it wasn’t. Check out Diesel Particulate Filter Shutdown Part 2.
