I have owned this pickup for over 2 years now (201 and have had nothing but trouble with the emission equipment. This diesel uses DEF to cut down the emissions according to EPA. If I use the cruise control and drive it at interstate speeds (78mph) I will get an error message on the dash after 2+hours(exhaust quality poor, max speed reduced to 55mph in 100 miles). Long story short, there is 1 nitrogen oxide sensor(NOX) in the front of the muffler and 1 in the rear of the muffler. The dealership has replaced 6 of these sensors already. I live 90 minutes away from the dealership so this is an inconvenience to drive there, wait at least 2 hours to replace part, and return home. Pretty much wastes 1/2 day. The thing I have noticed(although the dealership won't acknowledge it or upgrade the NOX sensors) is that once the message appears on the dash it will disappear again by cancelling the cruise control! All these 90min trips to and from involved using cruise control, then message would appear. I drove this vehicle 75+ mph for 380 miles one way, then returned home the next day without the cruise control on both trips. THE EXHAUST QUALITY POOR MESSAGE DID NOT APPEAR. I don't know how to get this message to a GM Factory Technician who might be able to solve this issue. Driving long distances without cruise control is a PAIN! But, I guess it'* better than wasting a 1/2 of my time for a problem that GM should have fixed 2 years ago!!!

I'm curious as to whether the Duramax Diesel 8-CYL have the same NOX sensor issues as this 4-CYL? I'm sure there are thousands of DURAMAX diesels on the road, and some GM Technician should have solved this problem by now??

My pickup is a 2018 Colorado Crew Cab 100th Anniversary Edition. Very sharp pickup now w/chrome add-ons! I have contacted a lawyer in Illinois who specializes in the Lemon Law, but am hoping that General Motors comes up with a solution first because I would enjoy using the Cruise Control again!!

What are lemon laws like in your area?

You've been taking this to them for two years, make noise about getting a free loaner car with unlimited miles while they fix this issue permanently.

Cruise control is very exact, and I'm guessing your drive is very flat. It might be that a little variance solves the problem . . . and the cruise control doesn't allow much variance. If your drive is hilly then that blows my theory.

Rattle your dealer'* cage about this ongoing issue. Since it is clear that they can't fix it, it is time for them to escalate. Add "I'm not going to allow this to continue until the warranty runs out so it becomes my problem" somewhere along the way, and maybe a bit of "are you going to fill my fuel tank each time I come out here?"

My guess is that they're changing sensors is because they don't know what else to do and need to tell you that they did something. This appears (to me) to be an unanticipated outcome that GM didn't see in testing, or didn't see enough to warrant a change. Either way, this is theirs to fix.

No, they don't.

That being said, I don't believe that NOX sensors are your problem either, otherwise the replacement units would have fixed it permanently.

This might be the right direction to go on this.

Also, I suggest you don't let this devolve into being just a cruise control issue or just a sensor issue. It is an emissions issue and a reliability issue.

One more thing: Since they are replacing parts etc. already, I infer that they have acknowledged the issue, and done so in writing. Make sure you have all of your paperwork together.

Moved from the "General GM Chat" forum to the "GMC/Chevrolet Truck/SUV" forum.

Is it possible to take it to a different dealer? That message can be set many ways. Not always a NOX sensor. Can be carbon on the after treatment injector(or in the cavity it sits in restricting def).Skewed sensors,Induction or exhaust leak,After market add-ons,Had one due to a leaking indirect injector. With out enough info it would be hard to help and given (as I understand) this vehicle is under warranty, I think contacting GM customer service or the GM zone rep is what I would suggest before a lawyer is involved. Once a mention of a lawyer, at least at the dealer level, the vehicle is pulled out and let sit till we are told what to do with it No body wants a buy back. We have had many vehicles brought to us at the request of GM for several reasons. It'* possible that they may suggest somewhere else to take it as you are not happy with the dealer you are dealing with. I know this doesn't resolve your issue but I hope this helps.