[MadMac]

Had to make a family emerg. trip to Calif. and on the way back home thru Colorado, truck went into "LIMP" mode. Stopped at Stevinson's Chev. in Lakewood to have truck checked. The Tech. went thru all the checks ( flow rate, Nox sensor(s) gaskets/wiring) all checked within spec.(spent 2.5 days) Left there and drove another 300+ miles, went into limp mode again, Stopped in Ogallala, Neb. at Schmidts Chev. and went thru a battery of tests and re-gens with no faults found, all "codes" cleared and back on the road for 150+ miles with no issues. Got back on the road the next day and drove 200+ miles and the DIC read 29% DEF remaining, so got the freshest 2.5gal jug of Blue DEF (under 45 days old) I could find and pored it in. Drove another 300+miles, and up pops prompt "DEF quality poor, will lower vehicle speed to 65MPH in 76 miles". It appears that when this prompt comes up, it appears at the same point in the limp mode sequence(reads the same mileage and never counts down and always at the 65mph portion of the limp mode also). This prompt stays up for about 10-20 miles and then, clears and the truck will accelerate and I can set the cruise and go back to normal driving. So, any GM techs. out there with a suggestion/fix?? All Gm checks have been done and we had this issue once in the first 5000 miles of ownership. I'm figuring it is something that is hard set in the ECM memory or whatever it is that sends a message from the DEF sys. to the ECM. All I know is that, I really like my truck, but I can't be having this happen every time I take it on a long trip, I get anxiety over this stupid crap (wife included). Chevrolet has got to step up to the plate on this one, they need to replace something in the system, because this is getting very taxing. Chev. needs to delete the LIMP mode speed parameters because this puts people in dangerous situations while traveling the nations Interstates, where there is not a dealer in every small town, We just got lucky. I want to thank both dealerships with the help and getting us back out on the road as soon as possible. MAC

 

[Rockcrawlerdude]

Sorry to hear about the fam emergency. Hope the family is all ok, bud.

 

[Burgess159]

What year is your truck again?

Also, maybe you ought to look into deleting your truck (depending where you live at). Wouldn’t have to worry about that nonsense. Just made a 1200+ mile round trip from Missouri to Ohio and back and no issues to speak of. 28.95 mpg on the way there and 29.5 on the way back. Best in the winter before I deleted was 26 something and only 28 in the summer.

 

[PowderMonkey]

Had to make a family emerg. trip to Calif. and on the way back home thru Colorado, truck went into "LIMP" mode. Stopped at Stevinson's Chev. in Lakewood to have truck checked. The Tech. went thru all the checks ( flow rate, Nox sensor(s) gaskets/wiring) all checked within spec.(spent 2.5 days) Left there and drove another 300+ miles, went into limp mode again, Stopped in Ogallala, Neb. at Schmidts Chev. and went thru a battery of tests and re-gens with no faults found, all "codes" cleared and back on the road for 150+ miles with no issues. Got back on the road the next day and drove 200+ miles and the DIC read 29% DEF remaining, so got the freshest 2.5gal jug of Blue DEF (under 45 days old) I could find and pored it in. Drove another 300+miles, and up pops prompt "DEF quality poor, will lower vehicle speed to 65MPH in 76 miles". It appears that when this prompt comes up, it appears at the same point in the limp mode sequence(reads the same mileage and never counts down and always at the 65mph portion of the limp mode also). This prompt stays up for about 10-20 miles and then, clears and the truck will accelerate and I can set the cruise and go back to normal driving. So, any GM techs. out there with a suggestion/fix?? All Gm checks have been done and we had this issue once in the first 5000 miles of ownership. I'm figuring it is something that is hard set in the ECM memory or whatever it is that sends a message from the DEF sys. to the ECM. All I know is that, I really like my truck, but I can't be having this happen every time I take it on a long trip, I get anxiety over this stupid crap (wife included). Chevrolet has got to step up to the plate on this one, they need to replace something in the system, because this is getting very taxing. Chev. needs to delete the LIMP mode speed parameters because this puts people in dangerous situations while traveling the nations Interstates, where there is not a dealer in every small town, We just got lucky. I want to thank both dealerships with the help and getting us back out on the road as soon as possible. MAC

Had to make a family emerg. trip to Calif. and on the way back home thru Colorado, truck went into "LIMP" mode. Stopped at Stevinson's Chev. in Lakewood to have truck checked. The Tech. went thru all the checks ( flow rate, Nox sensor(s) gaskets/wiring) all checked within spec.(spent 2.5 days) Left there and drove another 300+ miles, went into limp mode again, Stopped in Ogallala, Neb. at Schmidts Chev. and went thru a battery of tests and re-gens with no faults found, all "codes" cleared and back on the road for 150+ miles with no issues. Got back on the road the next day and drove 200+ miles and the DIC read 29% DEF remaining, so got the freshest 2.5gal jug of Blue DEF (under 45 days old) I could find and pored it in. Drove another 300+miles, and up pops prompt "DEF quality poor, will lower vehicle speed to 65MPH in 76 miles". It appears that when this prompt comes up, it appears at the same point in the limp mode sequence(reads the same mileage and never counts down and always at the 65mph portion of the limp mode also). This prompt stays up for about 10-20 miles and then, clears and the truck will accelerate and I can set the cruise and go back to normal driving. So, any GM techs. out there with a suggestion/fix?? All Gm checks have been done and we had this issue once in the first 5000 miles of ownership. I'm figuring it is something that is hard set in the ECM memory or whatever it is that sends a message from the DEF sys. to the ECM. All I know is that, I really like my truck, but I can't be having this happen every time I take it on a long trip, I get anxiety over this stupid crap (wife included). Chevrolet has got to step up to the plate on this one, they need to replace something in the system, because this is getting very taxing. Chev. needs to delete the LIMP mode speed parameters because this puts people in dangerous situations while traveling the nations Interstates, where there is not a dealer in every small town, We just got lucky. I want to thank both dealerships with the help and getting us back out on the road as soon as possible. MAC

Let

 

[PowderMonkey]

Let

Let me guess you were in the middle of nowhere and you had POOR DEF QUALITY all of a sudden appear, with a chime right? And the limp mode count down began.

 

[BnLdamaxs]

Burgess, did you fully delete meaning removed the hardware and running a straight exhaust? Or just programmed out all that ?

 

[Burgess159]

Burgess, did you fully delete meaning removed the hardware and running a straight exhaust? Or just programmed out all that ?

It’s tuned and turned off, and running a straight pipe from the turbo back with a muffler.

 

[BnLdamaxs]

What’s that setup sound like ? Pretty quiet or ?

 

[MadMac]

Let me guess you were in the middle of nowhere and you had POOR DEF QUALITY all of a sudden appear, with a chime right? And the limp mode count down began.

You hit it right on the head!

 

[Burgess159]

What’s that setup sound like ? Pretty quiet or ?

See my response to your question in the Tuning Forum thread you posted on there.

 

[PowderMonkey]

You hit it right on the head!

My fix was not to any def before I went on any sort of trip. I still can’t rap my head around that. I’ve had it happen twice since I quit that haven’t had a problem since.

 

[g-off]

had mine do the same in November, put a gal of def in drove until 19 miles to speed limited to 65 and it cleared itself. Took it to dealer and they did a refresh haven't had any problems since.

 

[Rooster]

I had an issue at the beginning like this except it was the air intake had a cut in the tube that was a factory defect which took 2 dealers , 2 tows and two hotel bills plus miss work to fix. Worst was GM ROADSIDE SERVICE. Would not reimburse me for out of pocket expenses for a factory defect. Look at the tube where the heat shield stops on it. The machine cut into the plastic just enough to put in limp mode.

 

[Skrow]

I had this happen to my 2016 around the 5-10,000 mark. Cant remember exactly at the moment. It happened about 3X before I got it resolved. Each time the prompt came up, I took a picture on my cell phone to show the dealer what the message was. I think my ECM was flashed once with an update and I would have to double check my paperwork on what else was done. Once I had issues resolved (all under warranty) i have be trouble free and getting ready to turn 51K on my truck. I'll post up more info after work. I believe one guy had a bad DEF injector that was causing his issue
So make them replace that. It definitely is DEF related.

 

[MadMac]

Let me guess you were in the middle of nowhere and you had POOR DEF QUALITY all of a sudden appear, with a chime right? And the limp mode count down began.

Yup, the first time it happened it started from the beginning and counted down. Once it got down to the 65mph limp portion, it stayed at 65mph then after 10-15 miles, the prompt went away and the truck ran back up to 80mph like nothing had happened and I could set the c.c. . Once in the Rockies, it happened again and we called a dealer in Lakewood and took the truck in. Spent the next 2.5 days there while they diagnosed the issue (everything cleared). Got back on the road and got close to Ogallala, NE. and had to stop at another dealer. Again, everything cleared. Back on the road and no issues the rest of the way home. Sorry for the late reply, haven't been on the site for a while. Mac

 

[MadMac]

I had an issue at the beginning like this except it was the air intake had a cut in the tube that was a factory defect which took 2 dealers , 2 tows and two hotel bills plus miss work to fix. Worst was GM ROADSIDE SERVICE. Would not reimburse me for out of pocket expenses for a factory defect. Look at the tube where the heat shield stops on it. The machine cut into the plastic just enough to put in limp mode.

I will mention this to the dealer when I take it in. Sounds plausible and possible to me. Thanx for posting this and sorry for the late response. Mac
P.S. If it makes you feel any better, we tried to get reimbursed for at least the cost of 3 nights of hotels, no such luck, because we weren't towed to the dealership for the factory warranty(36mo/36,000mi.) work!

 

[MadMac]

UPDATE: Truck's at the dealer as I write this. Since I had to leave for the C.R.of C. in haste, I'm 2500mi. over my oil service and getting the fuel filters, air filter, etc., done. They gave us a loaner, because S/M said it could take a couple of days or a couple of weeks, because they will probably need to get ahold of G.M. for the DEF issue (all tests, flow checks, gasket checks, NOX sensors, etc.) have been done and all the paperwork was given to him. Sooo…. I'll let you all know what was/if anything was done to fix this issue. I know one thing, this issue is now causing my wife and I anxiety issues when we need to use the truck on long trips. I have been lucky, whether it's cross-country trips on motorcycles (300+K miles), Off-roading in the deserts of Nevada/California (dirt bikes/jeeps/buggies), snowmobiles (25+K miles) here in Wisconsin, the last thing I want to worry about is the dependability/reliability of a vehicle we spent 43K on ( and it's paid for). Mac!

 

[MadMac]

What year is your truck again?

Also, maybe you ought to look into deleting your truck (depending where you live at). Wouldn’t have to worry about that nonsense. Just made a 1200+ mile round trip from Missouri to Ohio and back and no issues to speak of. 28.95 mpg on the way there and 29.5 on the way back. Best in the winter before I deleted was 26 something and only 28 in the summer.

I seriously considered deleting, but we've got a 150K/7yr. ext. warranty (thrown in by dealer) on the truck, so don't want to lose that right off the bat. But yes, would make one less thing to fill an/or worry about! Mac

 

[MadMac]

UPDATE #2: Well got the truck back from the dealer. Tech. found that the DPF pipe had 2ea. sensors that were intermittently communicating with each other, a nozzle that was cracked, and a flange/bung that the nozzle inserts into was also cracked. $1300.00+ part was ordered and will be here next week. S/M said he was 97% sure that it's my issue and should fix it, BUT...., like all things electronic?? Accomplished all the other servicing deeds that I needed done and it only cost me $260.00, which seems like a pretty reasonable price. Showed me the air and fuel filters, all were in need of changing. I put "slippage marks" on things to verify that things have been changed, since we live in the age of short cuts. Once the new parts are installed and we can take the truck on a reasonable trip, I'll do UPDATE #3. Stay tuned!! Mac
P.S. By the way Rooster, they did check the air pipe and found no defects. Thanx!

 

[Burgess159]

I seriously considered deleting, but we've got a 150K/7yr. ext. warranty (thrown in by dealer) on the truck, so don't want to lose that right off the bat. But yes, would make one less thing to fill an/or worry about! Mac

I understand. I had the extended warranty from the dealer as well. I however had not had any problems with my truck, but I was looking ahead and didn't want to have to worry about any of the emissions related problems and having to deal with them, since it seems like they never really get resolved and keep coming back. So that's why I went with it. I like the truck and this made it that much more reliable. I don't want to have to worry that when we go on a long trip if it is going to have a fit and decide to go into limp mode, like yours is.

I canceled my warranty and put the money from it towards the truck. Your situation my not work out the same as mine though if you were to do that.