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regen / particulate filter

16K views 14 replies 11 participants last post by  Andy B 
#1 · (Edited)
I'll apologize in advance - I am not a car expert and definitely not a diesel expert but I'm at wits end to figure out what is going on with our Colorado.

We have had to take our truck to the dealership 3x all for problems with the exhaust filter - all this in with only about 6800 miles (bought in late March 2017).

First time was about 60 days in to ownership. I drove the truck in to the city from the suburbs. I drove it for about 30 min at highway speeds before getting in to stop and go traffic in town. We took it to the dealership and they said the particulate sensor filter had "misfired" because the truck wasn't able to regen. They reset the sensor and we were on our way.

Second time was about 60 days after the 1st incident and occurred after I took the truck back to my home town; a drive of about 300 miles at 65-75 mph (so plenty of time to regen as many times as it wanted). We again took it in to the dealership and this time they claimed that GM was aware of the issue and they ordered a new filter from MI (took about 2 weeks to get it in and installed).

The truck is currently back at the dealership, we made it about 9 weeks from the last time. The dealer was able to determine that the truck has only regened about 17 times in 6800 miles in spite of multiple, hours-long, highway speeds trip. This last time started when I went out to the truck to drive to work. I got the error message "exhaust filter cleaning, do not stop driving". I live in a residential neighborhood and attempted to drive to a location away from elementary schools where I could drive at speeds greater than 35 mph, but in about 5 minutes I started getting an alarm and in less than 10 minutes the error message said that "cleaning failed, engine power reduced".
The dealership indicated that they were able to duplicate this error (less than 10 minutes to correct with no prior warning), but GM says that's SOP.


We are going to get the truck back and attempt to do what I call "burping the truck" and take it out for about 50 minutes once a week at highway speeds, but this seems insane to me that this is really the way this truck is meant to perform. We have had a brand new filter installed for less than 2000 miles and it's already catastrophically failed? Why is this time our fault when last time GM admitted that owners were having this problem? Is there anyway for us to force a regen?

Any insight would be appreciated.


UPDATE: 1/6/18
Well, now I drive a gas-engine Silverado. After the last time, the truck made it less than 400 miles before it throttled the engine back. Even better, I had just exited the Interstate Highway, going at speeds of 60-70 mph, I got a flashing dashboard light, and the truck slowed to about 10 mph with NO prior warning. We could've been killed if we had been towing a trailer on the highway and the thing came to a screeching stop with no warning. I had GM tow it back to the dealer and opened a customer complaint/problem file. GM insists that this is how diesels, and in particular, their diesel is designed to work. They refused to do anything saying, "we won't repair it because we don't believe that there is anything wrong or anything that can be repaired".
Thankfully the dealer we had purchased it from, (Newberg Chevy in OR) put together a reasonably similar deal for us on a crew-cab Silverado. I've never been happier to get rid of a vehicle. TBH, after this experience, I don't think we'll ever buy another Chevy. GM refuses to stand by their product and is just fine telling customers that's it's perfectly normal to have your car break down every 400 miles.
 
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#2 ·
You definitely have something wrong with your truck that Gm should fix. Likely a sensor. Couple guys here have had probs

Couple of thoughts of mine.

17 regens in 6800 miles is about right. It does it about once every tank of fuel which is a little over 400 miles average

The dealer can do a service regen, but you can't force a regen on your own at home.

My truck can knock out a regen in about 18 minutes. My commute is just under ten miles with speed limits maxing at 40mph and if it starts a regen one way, it'll finish the regen on the way home.

Occasionally I'll take the long way home if it starts a regen on a weekend trip, but you Shouldn't have to dedicate an hour trip to trying to do a regen
 
#3 ·
I agree with RockCrawler, that 17 regens in 6800 miles is about right (every 400 miles, it's doing one). I would say our truck is on par with that.

I know others on here who have had similar problems to you, but I don't know what the fix is. Do you have any modifications done to your truck, like a different intake or something? Could be what is causing your truck to give you so many fits with this, even though it's regenning in a normal amount of miles.

Also, have you been changing your oil? Or has your local dealership been doing it? I ask this because, while your truck is regenning in the correct amount of miles, it's still giving you issues. If say, you had too thick of an oil in there, it could cause the truck to produce more ash and thus, when it does regen, more crap gets stuck in that filter and it clogs up faster. Which could have been why your first filter failed way too early.

I know GM dealerships should know what they are doing, but if I remember, one person on here (or one of the facebook groups I'm in) said their dealer put the wrong oil in their truck. Some dealers just don't have a l lot of these trucks, or diesel truck in general, that they take care of. So when they get one, they may just do what they always do on other vehicles like use a standard 5w30 oil, rather than a DEXOS2 approved 5w30 (or 0w40) oil. I've done 1 change myself so far on the oil, and getting ready to do another one in less than 1,000 miles, and I am currently using Pennzoil Platinum Euro L 5w30 Synthetic (DEXOS2) oil. It is the lowest ash-producing oil out there that is approved that you can buy for these trucks currently. I'm sure GM has some AcDelco oil that is approved that they are supposed to use, but like I said, maybe not all are educated on what they are supposed to use in our trucks.

I would look into that and ask your dealer. May not be your problem at all, but it's something to look in to. Only other solution I could give you would be to delete the truck. But that isn't feasible for most people who just bought a truck for ~$40,000 and have less than 7,000 miles on it. I mean it would definitely fix it, but I haven't even done it myself even though I would like to.
 
#4 ·
I could go into a long story about my truck, not regen'ing, a vacation day taken away because i was at a shop in SD waiting on it to get fixed.

In the end, my truck has been in the shop four (4) times within the last 6-8 months. All due to the DEF fluid and the exhaust system. First time, they test drove, cleared the codes and did a test drive and forced(?) a regen. Way home from SD, got error message again, eventually, power reduced. Took pics on my cell phone of warning messages everytime and milage. They have reprogrammed the ECU, cleared codes and messages and the last time, replaced the DEF fluid pump. I have also heard of guys getting their DEF fluid injector replaced. I would have to look up my exact date of when the DEF Fluid pump was replaced, but it was probably a month ago.

Good luck, I plan on removing my whole exhaust with the DEF system after my warranty is up.
 
#5 ·
I have a 2017 Colorado with mini max. Two days after first oil change, got "Poor DEF quality. 160 km to 160 km/h max speed".
Temps at the time were cold enough to freeze DEF. Truck is parked outside. Truck driven minimum of 45 minutes to more than 2 hours per trip.
Took to dealer, Competition Chevy in Stony Plain Alberta. Initial feedback from service writer was no captured codes and DIC message won't clear.
So they are not sure how to proceed, I would imagine contact GM tech line next.
Got service rental (THANKS GUYS!) .
A few questions:
1) Anyone had same issue? What was the fix?
2) Truck has only used 10 L DEF in 11,000 km. Pretty frugal. Is this normal consumption?
3) How do you know when regent is happening? I see no indication.
Still really happy with truck and dealer, hoping this is not tip of long term problem
 
#6 ·
-Something is wrong with your truck, or you have bad Def in your tank
- Def isnt used during regen. It is used all the time, I think last time I checked on my scanner my usage was 1.6grams per 1km or something very small like that.
- tank of def is lasting most people about one oil change interval (5.5gal used in 7500miles) it seems your usage is about half of normal.
 
#7 ·
Took the truck to the dealer. No codes captured and could not reset Poor DEF Quality on DIC. Did a bunch of tests, both NOX sensor readings, DEF quality, DEF injector volume test. All within normal parameters. DID ECM UPDATE TO LATEST VERSION.. After all these tests, system would let tech reset DIC. Never did find a mechanical problem. Been running fine ever since. Continue to be happy with truck and dealer, Competition Chevrolet in Stony Plain AB.

Again: Is there and indication in a STOCK truck that DPF regen is taking place? Perhaps only seen on a programmer?
 
#9 ·
I bought BiScan (Android) and a bluetooth OBD so I could do a service regen! I can do it. My experience mirrors many on the site. GM is no help. The customer service is company protection not help customers. I use only pennzoil Euro-blend Dexos2 (low Ash) and change oil every 5K. I changed my fuel filters at 1K and had little black particles which appeared to be plastic shavings. Over the course of time I also had a incorrectly installed NO2 Position 2 cable resulting in 3 replaced sensors, because when replaced and re-plugged in it appeared to work. A mechanic looked careful before the 4th. Anyway during service on 2 occasions the dealers could not force a service re-gen. However after multiple limp modes, I determined I would handle this myself. I ran 2 service re-gens back to back in my driveway. Truck smelled funny, but in 14K miles this ghost has gone away. I feel it was something to do with the exhaust injector. No way to know, but YOU CAN FORCE A SERVICE REGEN if you have the right tools. Also, loaded OBD fusion on my iPhone and using the OBD bluetooth and my phone I can see the parameters and capture weird stuff. Since I bought the 20 dollar reader and app, murphy went to someone else truck because my issues have ceased.
 
#10 ·
I have a 17 Colorado with a babyMax. In the last 1.5 years & 37,000 miles, it's been in the dealership 3 times to replace the particulate sensors. Opened a case with the BBB since there is something wrong with (some/my) GM diesel vehicle. My turbo fan got bent and they replaced it. The next day, check engine light came on. This was right after I told my wife seems like the truck is "good" during a drive.
Dealership said it was the particulate sensor AGAIN. Sensor is bad in less than 3,000 miles. They have had it in the shop almost a week and said the dont know whats wrong. GM TAC had them run lots of diagnostics. Dealership states that they ordered and will replace the Diesel Particulate Filter. I feel they are just grabbing at straws.
 
#11 ·
I have a 17 Colorado with a babyMax. In the last 1.5 years & 37,000 miles, it's been in the dealership 3 times to replace the particulate sensors. Opened a case with the BBB since there is something wrong with (some/my) GM diesel vehicle. My turbo fan got bent and they replaced it. The next day, check engine light came on. This was right after I told my wife seems like the truck is "good" during a drive.
Dealership said it was the particulate sensor AGAIN. Sensor is bad in less than 3,000 miles. They have had it in the shop almost a week and said the dont know whats wrong. GM TAC had them run lots of diagnostics. Dealership states that they ordered and will replace the Diesel Particulate Filter. I feel they are just grabbing at straws.
On my truck, on the third replacement of the NO2 Position 2 sensor, the mechanic found an incorrectly assembled harness for that connector causing corrosion to simulate a failed sensor. I bought the paid version of torque and biscay to service and regen myself. I had an issue where it would not regen and 2 times the dealer had issues with a service re-gen. After the last service, I performed 2 re-gen's and all seems good with the exhaust system. GM customer service has no intent of working with you. In light of their legal problems they are working a prevent defense. Now that Ram is selling the eco diesel again, we have an option. I have 2 neighbors that went with the Ram and are loving the trucks, one has 22,000 and the other 47,000 and neither has had any engine issues. Just saying....GM may loose this market.
 
#12 ·
Lose the market to FIAT?! Talk to those folks again around 90k, that's about the design life of your average dodge. Can't have improved with FIAT.
 
#14 ·
One would hope they would have taken care of that at the dealer if the recall was issued at the time.
 
#15 ·
Been having the same problem with my 2017 canyon. It kept throwing a particulate matter sensor code. I replaced that. The code came back within 50 miles. I was at wits end myself. Changed the oil and filter about a thousand miles ago. Light went out on it's own. Hasn't been back in sense.
 
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