2015 Yukon Denali lag/hesitation

mcclam · February 13, 2015

We received a call today that our 2015 Yukon Denali is ready to be picked up after spending 21 days at the dealer for repairs. This is the second attempt to fix a lag/hesitation problem that GM says is normal for this vehicle. GM states that these new vehicles have a farther pedal travel than other models and it is “normal” for a 6.2L to behave this way. I have a 2010 6.2 that drives perfectly. This lag/hesitation does not happen all the time, just randomly and I consider it a HUGE safety problem. If it were a pedal travel issue then it would happen all the time . The dealer was able to duplicate the problem but was told by GM that the procedure they used was not proper diagnostic procedure and that the system is normal.

This is the third time the vehicle has been in to the dealer for various problems including; no heat/defrost on our only icy morning this year even after warming it up for twenty minutes ,broken or misaligned rear seat bracket, front seat memory not working, a new steering column due to a grinding while turning, and a constant pull to the left while driving at all speeds. I am extremely disappointed in GM’s response to these issues after spending well over $71,000 . We signed the contract for this vehicle on Oct.23,2014 and were promised a delivery of Oct.25,2014. The vehicle finally arrived Dec.14,2014 and has had multiple problems ever since. I am tired of being led along by GM not standing behind their vehicles. It is very disappointing to me because up till now I have been a loyal GM customer and have Six GM vehicles currently registered to me personally and many more in the business that I own. I am frustrated that I have little to no recourse in this issue. I would advise anyone considering a new Yukon Denali to be Extremely careful because I would not want anyone to have to go through this like me.

Carder09 · February 13, 2015

Sometimes ya get a lemon.

SouthernSilveradoGuy85 · February 13, 2015

How many miles is on it? The trans is probably still in learn mode.

mcclam · February 13, 2015

It has 1,335 miles to date. My company operates several newer model Chevy and GMC trucks (2007-2014) and have never had any problems such as this. My last 2007 Tahoe was great and so was the customer service. I really wonder why its different now. We like the truck, just wish GM would quit stalling and fix it. Had a service manager from another dealer tell me that as more complaints come in they will probably come up with a fix. Till then I really hope it doesn't stall when my wife is crossing traffic. The dealer we took it to told us it needed a new computer but then GM stepped in and would not release one because they say it is not setting a code so it is operating normally. Weeee....

SouthernSilveradoGuy85 · February 13, 2015

I believe it's still in learn mode. I'm not the only one that had mine shift hard into 2nd sometimes but after 1-2,000 miles it completely stopped so I figured it was in learn mode. Maybe yours has an actual issue, I'm just saying something that is normal that it could be. You should take it to a transmission shop and get them to look at it.

EDIT: Ya I forgot about TQ management which makes more sense than learn mode, could be a little of both also.

crafferty · February 13, 2015

There's nothing wrong with your vehicle, GM is correct in that regard. I have experienced the same issue with my 2014 Silverado (6.2L & 4x4). What I found is that disabling the torque management with an aftermarket tuner such as a Diablo Sport fixed any and all hesitation issues. At first I thought it was the combination of AFM and TQ management. But after the last couple weeks of playing around with different settings it seems that the TQ management on our 6.2L engines is over bearing. If you have any questions feel free to send me a PM.

mcclam · February 14, 2015

Yes Crafferty you may be correct on TQ management. I had a 2000 5.3 that I put a Whipple supercharger on and we battled the TQ management for ever. Finally got it figured out with a custom written program. This issue on the Denali seems to be more prevalent when accelerating at a low to moderate rate. Have never experienced it when accelerating hard. It also occurs well before the 1-2 shift point. We are going to keep driving it for now and see what happens. GM has informed us thru the dealer that this is an all new system(direct injection) and it performs differently. We will see.....

crafferty · February 19, 2015

Is your Yukon Denali the 6 or 8 speed? The 6 speed I know for sure will be TQ issue. The 8 speed could be a whole different ball of wax.

DreamCadi · February 21, 2015

GM hasn't really been good about giving us control over how we want our engines, transmissions or suspensions to work, I think if they would allow us to control them (Performance mode, eco mode, suspension height etc) Jeep is doing this and I think it's great. Why not give us a performance option in the DIC or Nav screen that allows us to change some vehicle dynamics?? I understand what everyone is talking about here on this thread but it appears not all of us are accepting of the engine lag and would like better response from GM on how to improve this condition.

f8l vnm · February 24, 2015

I mean no disrespect to any of the guys saying this but " Its still learning" has to be dumbest thing I hav e ever heard .

My transmission is still " learning " at 4700 miles, Still learning to be awful that is .

I beleive this is the POS tunning GM has placed on these cars,

SouthernSilveradoGuy85 · February 24, 2015

I mean no disrespect to any of the guys saying this but " Its still learning" has to be dumbest thing I hav e ever heard .

My transmission is still " learning " at 4700 miles, Still learning to be awful that is .

I beleive this is the POS tunning GM has placed on these cars,

The reason I said that is because in my situation it stopped shifting hard after about 1-2,000 miles and other's have stopped also. Your's being that it's still doing it at 4,700 then no it shouldn't be learning anymore. The transmissions are in learn mode to learn how you drive for first few hundred miles.

mcclam · February 25, 2015

Well an update on our hesitation problem. We recently drove over 2,000 miles in less than three days at all speeds including hammer down through the desert and had absolutely no issues with lag/hesitation. Learning mode? Who knows. Not GM that's for sure (or they are not telling). Only issue we had is that after driving 12 1/2 hours with the ac on recirculate due to dust allergys we got the dreaded mildew smell. I switched it to fresh air the next day and it is better but still noticeable. I don't want to be a constant complainer but this vehicle really is testing my loyalty to GM and there products. (we had many mold /mildew problems with our last three Tahoes and my 2003 corvette zo6. I do the BG condenser cleaner myself and have found it to be helpful. Thanks everyone for your help and comments.

Zig · March 2, 2015

I have the same problem with my 2015 Tahoe. It has the 5.3 liter engine. It only happens under load when the engine is warm, but not fully up to temperature. The dealer says it may be an engine software issue and says there are no fixes to date. This is my third Tahoe and it is very disappointing to say the least.

Wrench589 · April 16, 2015

Hmmm, our Yukon XL Denali just started acting up. I think it's a TQ management issue too, but the symptom is SIGNIFICANLTY worse then reported here. It literally quits on the road. Total lack of power, and coasts to a stop, as long and the accelerator pedal is kept depressed. The engine is essentially at an idle when this is happening. If it had happened on a busy freeway, I'd be in the hospital or the morgue right now, cause it's almost like the brakes come on!

Did some testing and slipping it into neutral and the engine goes to idle. Tries to recover but just stumbles a couple of times. Need to let off the pedal and seems to sort of reset itself. If left in gear, the whole vehicle bucks as its slowing down.

And the best part - can smell something burning. Coming from either under the dash or under the vehicle. Definitely not under that hood as I popped the hood to check.

MIL is on. Only code I can read with my Insight code reader is P0131 - low O2 sensor voltage. So, could be a bad O2 sensor, but I cant see that throwing the ECM into such a state! Should simply go into open loop mode, throw a code, light the MIL, and wait for you to get it repaired. This is fricken' dangerous. My wife refuses to drive it until it's fixed, and even them we'll have to see. And, I have 3 small kids, to boot! Nice, eh?

Anyway, it's going to the dealer so we'll see what they come up with but is anyone has any insights or seen this, any input much appreciated.

Leslie Wasson Green · September 30, 2016

Well an update on our hesitation problem. We recently drove over 2,000 miles in less than three days at all speeds including hammer down through the desert and had absolutely no issues with lag/hesitation. Learning mode? Who knows. Not GM that's for sure (or they are not telling). Only issue we had is that after driving 12 1/2 hours with the ac on recirculate due to dust allergys we got the dreaded mildew smell. I switched it to fresh air the next day and it is better but still noticeable. I don't want to be a constant complainer but this vehicle really is testing my loyalty to GM and there products. (we had many mold /mildew problems with our last three Tahoes and my 2003 corvette zo6. I do the BG condenser cleaner myself and have found it to be helpful. Thanks everyone for your help and comments.

Quick question. I know this thread is older..but you said you got a mildew smell from being in recirculate? I asked my dealer when I bought my truck what to run the ac on and he said "recirculate, ALWAYS recirculate"? Uh-oh. Am I going to get mold smell?