[Barry Allen]

2018 diesel MT sedan

Leaving the post office parking lot I got the message displayed saying "Engine Power Reduced" and the CEL is on. Engine wouldn't really run above about 2,200 RPM so it was slow getting to work. Restarting the car has a new message saying the particulate filter is full and continuous driving is necessary.

Any suggestions? After work I'm going to take it out and do some highway driving to see if the particulate filter will regen and clear up the issue. The next appointment at the dealership is on Monday so if it isn't self-correcting I'll have it there then.

 

[Barry Allen]

DPF needs a regen.

At work in the AM I waited a few minutes and restarted the car. It immediately flashed a warning message about the particulate filter being full and needing continuous driving.

Hopefully a 20-30 minute drive on the highway will resolve it (Active Regen).

After work I took it for about a 20 minute highway drive. It would never get above 75 mph on flat land and it would not enter active regen. Fuel economy continued to be about 52-54 mpg and it just wouldn't begin a regen cycle. I went to the auto parts store and they pulled a p2463 code from the OBD stating the particulate filter was full of soot. With the drive from the store to my gym the DPF warning message would not clear off the display and the car chimed at me about every 2 minutes.

When leaving the gym the engine power was still reduced but no DPF warning message. Then, about 2 blocks away, the engine power restriction lifted suddenly enough that it about gave me whiplash.

If not, a trip to the dealer is in order (Forced Regen).

I don't think they have to do a forced regen now, but the CEL is still on so they'll have to figure out what is going on with that.

 

[Barry Allen]

Today I started the car to leave work and the CEL is gone. I guess the DPF eventually regenerated itself and cleared up the fault codes.

I'll still go to the dealership appointment and see what they can recommend, but I'm guessing the short bit of cold & damp weather we had caused some soot to accumulate as a mush of slime in the DPF due to a couple days of stop & go driving.

 

[Barry Allen]

Just to add I read in related threads this might not be a plugged DPF but possibly a faulty or intermittent pressure sensor.

Dealer will be able to figure out for sure.

Good luck and keep us posted next week.

I would have liked to get the car to the dealer while it was doing it's thing with the error messages. I fear I'm going to show up Monday with a perfectly functioning car and be told "We can't duplicate the problem." I don't want a repeat of this unless it's timed perfectly to when I can take the car to a dealership because I have a job to be at so otherwise I'm driving the car. When the DPF message popped up on Friday evening I feared the worse and two things could happen: 1) It will be fine and the dealership can fix it Monday, or 2) driving it to work and places over the weekend is really, REALLY going to break some expensive things.

 

[Barry Allen]

Drive in a higher gear. Raising the rpms. It'll help get the job done faster.

When it was in limp mode I coaxed it onto the interstate for about 15 minutes. Flooring it in 6th gear would get me 70 mph and about 2,400 rpm, would go no faster unless it was a downhill grade. The engine would not enter a regen cycle; I could tell because fuel economy held steady at about 52 mpg.

 

[Barry Allen]

That should say LOWER gear. LOL.

No matter what gear the engine would not run above 2,400 rpm.

 

[Barry Allen]

Barry Allen, What is your normal commute distance?

Straight to work and return is about 4 miles, but some days have longer trips to do other errands.

 

[Barry Allen]

That is the problem there. These clean diesels need to be driven or the regen never runs/completes.

That's not a problem with my car. It sees regular highway driving. My parents live about an hour south of me and almost every week week I visit them to help them as they are both disabled. With the visit I get to have a few meals, do laundry, and they have cable TV with a DVR that records my favorite shows. So the car gets regular highway use where I've observed regen of the DPF.

The past weekend before my troubles was a Saturday where I drove 120 miles to a cousin's wedding. On Sunday I drove 175 miles to my parents' house. On Tuesday I drove 50 miles to my house. All of this was at highway speeds where the car could have done a regen cycle. Wednesday and Thursday was commutes to/from work in some cold & wet weather. I've read a few people who think this is a recipe for problems because the dampness and temperatures combined with diesel soot forms a kind of snot that can clog up the DPF it it's not run hot enough to clear all the moisture out. Friday morning was when the car started having problems and then Saturday evening was when it magically fixed itself.

So the car car had plenty of highway driving in the prior weekend where it could have regen the DPF, but it didn't. Then, when the error messages were on the dashboard, highway driving didn't trigger any regen that I could notice. It just magically fixed itself.

 

[Barry Allen]

That's ok. All you can do is try.

Semis normally operate around the 1500 range. They don't normally go above 17 or 1800 when it's time to grab a higher gear.
When the regen kicks in. IIRC. I think it gets knocked down to 1600 or less.

I no longer drive a dpf truck. So I"m not sure on the exact rpm. The current truck I'm driving now is an 07 and I've been driving it for 2 1/2 years now.

At 70 mph and 2,400 rpm the car should have easily been in a regen cycle. It won't affect power or engine speed, but fuel economy takes a plunge with the extra fuel being used to regen the DPF.

The car just wouldn't go into a regen cycle. The engine was fully warmed up and it would hold a steady 70 mph and be at about 54 mpg fuel economy.

 

[Barry Allen]

Dealership had the car all day today. Their diesel technician (mostly works on Duramax trucks) talked to me with all the information I could provide. His thoughts on the matter were the ECU was somehow not analyzing the various sensor inputs correct. It seemed like a BS excuse but he said there was a software update to apply to the car. 10 minutes later he informed me that my car already had the latest software on it so his testing was going to be doing a test drive of the car and using a computer to manually trigger a DPF regen to see if everything was reading and responding correctly.

At the end of the day the dealership gave me a loaner car since they apparently need to keep my car until at least tomorrow. The service writer thought the technician was finishing my car up at the end of the day only to find out he was nowhere to be found. When they called him on his phone he was already off work and at home. He told them my car was not able to be drive, so he's got something taken apart or something else going on with my car that they were not specific about. The communication with this dealership isn't great from what I see so far.

My loaner car is a gasoline Cruze with automatic transmission. Fuel economy is pretty good but it's got zero power unless you are flooring it everywhere you go.

 

[Barry Allen]

The dealership service department texted me the following:

FOUND P2463 PASSED AND FAILED BUT NO MIL SET AT THIS TIME. FOUND 33% SOOT MASS IN DPF. FOUND COUPLE BULLETINS INSTRUCTING TO CHECK ECM CALIBRATION. FOUND CALIBRATION UP TO DATE. NO OTHER BULLETINS AT THIS TIME. PERFORMED REGENERATION AND ACHIEVED EGT1-650F. EGT2-1200F. EGT3-1125F. (IN SPEC) REGENERATION WAS SUCESSFUL. CONTACTED TAC 8-4780278480. AT THIS TIME WITH ALER IN SPEC AND SUCESSFUL REGENERATION PERFORMED, THERE SEEMS TO BE NO PROBLEM.

The service writer then said the technician updated the ECM and performed a couple bulletins. That's conflicting information given that the technician found the ECM had the latest software available and there were no other bulletins listed to perform. With the technician doing a driving test it appears he was easily able to get the EGT above 1100F for a regeneration, so as long as the ECU triggers the regen appropriately it should have no trouble cleaning out the DPF.

It's just baffling what went wrong. I can understand I might have reached a situation where the car was due for a DPF regen and then some city driving (commute to the post office, then work) interrupted the regen enough to cause a problem. Still, the fact that driving the car on the highway wouldn't trigger a regen when the instrument panel was warning me it was desperately needed is strange. I just can't figure out why the car didn't immediately regen when I was going fast enough and the entire drive system was up to temperature.

 

[Barry Allen]

Regens are quirky beasts with this car.

I agree, but this is just some very bizarre behavior.

First, the vehicle has a dedicated "DPF FULL" indicator light in the instrument cluster. It's with the speedometer. I can see it light up when the engine first starts as a check on all instrument cluster lights. That indicator light never came on even when the multi-function display gave me the text readout that the DPF was full and continuous driving was mandatory. Why have a light when it doesn't get used?

Second, if the multi-function display was giving me dire warnings that I need to continuously drive the car to clean the DPF, why wouldn't it enter a regen cycle when I was at highway speeds? The fact that it wasn't regenerating when the display told me it was necessary was very strange.

Third, the display got worse for a short while when that error message wouldn't clear from the screen and the car was audibly chiming at me every 60 seconds or so. That made me nervous that something was really going to be broken over the weekend of driving the car to/from work.

The fact that the car magically cured itself was strange. First the DPF error message went away. Two blocks later all the engine power returned (and I did notice a very short regen cycle while doing some 45 mph driving on city streets). Then the CEL turned off about a day later. All this and the only stored error code was the DPF being full when the dealership technician was able to determine the DPF was about 1/3 full when I arrived at the shop

I honestly hope the problem goes away. I don't want intermittent issues to come along that the dealership can never diagnose unless I bring the car in RIGHT NOW when it's happening, because that's always a major pain to deal with.