It would, but some dealerships just don't want to deal with it.

Let's put it this way, it's either that or they're incompetent. No way you should have to be the one to uncover the relevant TSB.

 

After sending the TSB (which describes the exact problem that I am having) the service advisor replied that it is for 'stock vehicles' and he still maintains that the oversized tires that I have on there are the cause of the problem. Also referring to the problem that I am experiencing, he stated that 'We are not experiencing that problem as of yet'. I don't think they have even tried to duplicate the problem. Now they want to charge a rate of $105/hr to perform the TSB. Does anyone know if I have to pay for repair work stated in a dealer issued TSB.

Anyways, I don't think these guys know what they are doing so I have contacted GM service to see if they can help.

 

Print and hand them a copy of the Magnuson–Moss Warranty Act and ask them to provide proof that your wheels have a direct causal affect on the issue. Advise them that should they fail to do so, you will pursue legal action.

I hate dealers like that, trying to scam customers out of every dollar.

 

I sent an email to my service adivsor to see if he could provide proof that my aftermarket wheels and tires are the cause of the problem and if he had tried to duplicate it, he replied:'No I cannot provide proof. We have not duplicated your issue, only saw the history codes. If this problems only happens once in a while, it will difficult to duplicate'

 

They have the codes, they have the TSB addressing them, they cannot provide proof of causality between your wheels and issue.

Hopefully GM CS will step up and set this dealer straight, otherwise ...

 

OK guys. All that matters other than un-sprung weight is RADIUS or revolutions per mile.

Stock 265/65/18 according to http://www.discounttire.com/dtcs/infoTireMath.dos

has 639 rev/mile. New 305/50/20 has 630 rev/mile 9/639 = 1.4% Difference. No way can the base vehicle tell the difference.

 

Just an example,

Standard tire size for 2013 CADILLAC ESCALADE HYBRID 4WD:
(in case of different tires in front and rear the dimensional data are valid for driving or rear wheels)
Standard tire size:
285/45 R 22
Tire width (mm):
285
Tire sidewall factor:
45
Rim size (in):
22
Total wheel diameter (mm / in):
815 / 32.1

http://www.automobile-catalog.com/ti...ybrid_4wd.html


How many miles do you have on you're tahoe Hybrid ? and did you get an extended warranty?

Also the hybrid Original Manufacturer Warranty should read like this,
Warranty

36/36,000 Basic (mths/miles):
60/100,000 Powertrain (mths/miles):
72/100,000 Corrosion Perforation (mths/miles):
60/100,000 Roadside Assistance (mths/miles):
96/100,000 Hybrid Electrical Components (mths/miles):

http://www.cars.com/gmc/yukon-hybrid/2008/warranty/

http://www.chevrolet.com/owners/warranty.html

Maybe you should find a new dealer. Do you have a GMC dealer nearby you could try?

Maybe send the service writer this forum so they'll have a chance to learn a few new things about the Hybrid system.

 

Approximate mileage is 76K. I purchased the vehicle used and also purchased an aftermarket warranty.

As of today, I've contacted GM CS and they said they are going to contact the dealer. I'm expecting a call back tomorrow afternoon.

 

Pon, if the dealer did NOT clear the stored codes from last visit, there should be more information IFF they dig just a little bit deeper. When many codes set, a specific list of vehicle operational parameters are stored in something called a Freeze Frame. GM can use this to pinpoint what was going on when the code set.

The problem is. Most old wrenches... like me... will get in a habit of clearing everything and "let's see what comes right back". OK that works good on my old Lumina with a bad O2 sensor. The check engine light comes back in less than 5 minutes.

Hybrids are different! Way different! A code like what made yours quit may only come around once in a blue moon after planet alignment and solar flares. So P0AC4 just means that the hybrid master computer told the engine computer to turn on the light. If the request came from the transmission computer it would have P0700. The engine computer still has the ONLY wire directly to that light. Legacy technology from when the engine was the lead dog.

Next step. We see a request for the light. OK. Who sent it? Hybrid. OK. Why?

The dealer can go deeper than the guys at Orilleys and get the freeze frame from the hybrid computer and others. They need to learn to do this FIRST. Service guys... First the interrogation, then you can dispose of the wittnesses.

There are data parameters in the hybrid freeze frame that could point straight to the battery if that is the problem.

 

Why aren't dealers better trained to handle these types of issues? Why is someone like the op resorting to Internet forums to get some semblance of real help? Pretty poor showing on Chevys part if you ask me. I know how it is a bit of a relationship thing but man these are cels we are taking about not some mysterious whistling noise being diagnosed.

Curious to see how this is ultimately handled.