LOW POWER MODE!! GM exhaust Nightmare!!! after cleaning exhaust filter 2020 HD

Sniperdan · March 26, 2020

On 12/10/2019 at 9:24 AM, Scot Knutson said:

My GM Diesel exhaust system nightmare!

I bought a 2017 2500 LTZ midnight edition It worked fine for a year, then my GM exhaust system nightmare began. It all starts with cleaning exhaust filter continue driving then within 10-20 minutes it goes into Limp mode always at highway speeds and often under load. This happened over 6 times and would have happened more had I not left it at the dealership for so long and not been able to drive it.

3 weeks ago I finally had enough and I decided to trade it in for a 2020 2500 High Country. This weekend as I was towing snowmobiles up to the mountains in Colorado with less than 1,500 miles on the truck it said it was cleaning the exhaust filter keep driving. i continued to drive at 70 MPH and within 20 minutes it went into Low Power Mode and the check engine light came on. I was then stuck doing 20 MPH on mountain passes going into Vail.

I have dropped the truck off at Chevy AutoNation North in Denver. I may be at the end of my road with Chevy trucks???

I have been a loyal GM truck owner for over 20 years ever since I was in the Marines.

Scot Knutson

I am wondering if maybe there is something wrong with your fuel source? It seems pretty strange to have the exact same issue with 2 different trucks, especially when it is not a super common issue with these trucks. That would lead me to believe that either something is wrong with the fuel you are using, something wrong with the DEF you are using, you are using an additive it doesn't like, or you are driving it in an unusual way. I can't really think of what other variable could cause the same issue with 2 completely different trucks.

redwngr · March 26, 2020

Are you running any fuel additives?

Ben2013 · April 2, 2020

I have a 2020 Silverado 2500HD W/T it has about 1,250 miles. I've noticed twice now a strong diesel smell in the cab, enough to where you have to roll down the windows. When you stop at a light white smoke comes out from under the hood by the wiper cowl. Seem to be running fine, no lights or messages displayed. I guessing its in regen mode. I plan on taking it to the dealer and letting them have a look. I purchased this truck with the Duramax diesel rather than the new 6.6L gas motor for better towing capabilities, but if this diesel smell cant be resolved then i'm definitely going to be trading it in. Should have just kept my 2012 gas hog 6.0L.

redwngr · April 2, 2020

28 minutes ago, Ben2013 said:

I have a 2020 Silverado 2500HD W/T it has about 1,250 miles. I've noticed twice now a strong diesel smell in the cab, enough to where you have to roll down the windows. When you stop at a light white smoke comes out from under the hood by the wiper cowl. Seem to be running fine, no lights or messages displayed. I guessing its in regen mode. I plan on taking it to the dealer and letting them have a look. I purchased this truck with the Duramax diesel rather than the new 6.6L gas motor for better towing capabilities, but if this diesel smell cant be resolved then i'm definitely going to be trading it in. Should have just kept my 2012 gas hog 6.0L.

Certainly not normal.

Tomato · April 2, 2020

33 minutes ago, Ben2013 said:

I have a 2020 Silverado 2500HD W/T it has about 1,250 miles. I've noticed twice now a strong diesel smell in the cab, enough to where you have to roll down the windows. When you stop at a light white smoke comes out from under the hood by the wiper cowl. Seem to be running fine, no lights or messages displayed. I guessing its in regen mode. I plan on taking it to the dealer and letting them have a look. I purchased this truck with the Duramax diesel rather than the new 6.6L gas motor for better towing capabilities, but if this diesel smell cant be resolved then i'm definitely going to be trading it in. Should have just kept my 2012 gas hog 6.0L.

Definitely not normal. There was a TSB on the previous generation for a loose turbo connection causing strong diesel smell in the cab, if I remember correctly...Mine did not do it, fortunately.

Edited April 2, 2020 by Tomato

Ben2013 · April 3, 2020

22 minutes ago, Tomato said:

Definitely not normal. There was a TSB on the previous generation for a loose turbo connection causing strong diesel smell in the cab, if I remember correctly...Mine did not do it, fortunately.

Funny you should say that, the first time it happened once i made it to work i popped the hood and looked towards the back of the motor to see where that white smoke was coming from and noticed that there was some white/black spots on the drivers side valve cover just under the turbo.