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-   GM Hybrid Trucks, Cadillac Escalade Hybrid, Chevrolet Tahoe Hybrid & GMC Yukon Hybrid (https://electricvehicleforums.com/forums/gm-hybrid-trucks-cadillac-escalade-hybrid-chevrolet-tahoe-hybrid-gmc-yukon-hybrid-69/)
-   -   Power Brake Problem? (https://electricvehicleforums.com/forums/gm-hybrid-trucks-cadillac-escalade-hybrid-chevrolet-tahoe-hybrid-gmc-yukon-hybrid-69/power-brake-problem-21046/)

kdawg1 03-30-2009 11:38 AM

Re: Power Brake Problem?
 
Yes, I'm sure there are a number of different scenarios that can occur to cause the messages and the almost 100% brake failure. Believe me, we're trying to remain positive as we love this truck. I haven't purchased a GM vehicle since my '96 Cavalier's transmission blew up at 30,000 miles. We figured we'd take a big chance on this Tahoe Hybrid, buy American again, and be off n running with one helluva nice truck. Just the fact that it's in the shop (before 1,000 miles) has me taken back a little. I've owned 3 Nissans and my wife has had same Honda for about 10 years and none of these cars saw the inside of the service area outside of oil changes. Our Chevy service manager (at the dealer) told us "...well, there are alot of moving parts to this vehicle so these things happen...". They don't get a hall pass because "there are alot of moving parts...". There are alot of moving parts to plenty of cars out there (including the ones i currently own). I'm assuming the truck will come back from the dealer and the problem will be solved... Assuming can get dangerous, though.

Dunebuster 05-11-2009 01:27 PM

Re: Power Brake Problem?
 

Originally Posted by Defender (Post 197946)
Yes. My Tahoe is now being repurchased by GM per Lemon Law. They believe they have found a fix as a firmware update was released this week that necessitated a free battery change. I have not been able to test this last repair as we are not in legal process and they have sort of limited my use to 7500 miles or else I have to pay about 0.50 per mile when they buy it back. You'd think that after they sell you a car that turned out to be bad, they would bend over backwards to accomodate you. Nooooo. They only provide what the law requires. So in my case, if they buy back my Tahoe, it is as if I leased the vehicle for $800 a month. They want you to put me on another Tahoe Hybrid but I have to pay about 2500.00 in usage also.

Your circumstances was not similar to mine although the same messages appeared. I would lose my brakes going downhill too but not get it back until the dealer clears the code. Scary. Then it progressively got worse. I would get the messages but it would not last long enough to trigger the check engine light. Then work fine for a day and be dead the next day. Twice I drove about 100 miles one day and the vehicle was completely dead the next morning. Frustrating!

They have changed my battery twice. Each time with a higher capacity. The last time I was in the dealership, they were able to drive the vehicle to the service bay then once it got there it would not start anymore. I have been stranded and had to be towed 3 times. So tired of this and just wanted a vehicle that works. But GM wants to negotiate the replacement.

The service manager told me GM is still learning from all this. So we are all expensive guinea pigs.

I have started posting about this on my new blog which will contain info about the new firmware in a few days. Check it out - Chevy Tahoe Hybrid Problems


Did they replace the 12V battery or the actual Hybrid battery?? There's thousands of dollars in difference here??

2tall 05-17-2010 09:30 AM

Re: Power Brake Problem?
 
gltech, I have been having a similar issue with my 09 Sierra. It didn't start until the dealer installed a software upgrade that was supposed to "fix" a faulty battery charge indicator.
Sometimes while coming to a stop, the truck suddenly lurches as if someone just bumped me from behind. Other times, on takeoff, when the system is in autostop mode, it will hesitate and then lurch ahead, like a car with a faulty autotmatic transmission. I have not noticed any dash lights; the dealer couldn't pull up any codes, and Onstar hasn't reported any diagnostic problems.

Hillbilly_Hybrid 05-17-2010 11:41 AM

Re: Power Brake Problem?
 
2Tall; if this is happening in and around Auto-Stop, have the dealer put the Tech 2 on it and look for Auxillary pump performance problems. The bumping and lurching may be a clutch slipping due to erratic Aux pump speed hence flow and pressure control.

The dealer can and should call Technical Assistance for more information.

xfordguy 06-15-2010 04:03 PM

Re: Power Brake Problem?
 
I've had the power brake failure problem twice in the last few weeks on my 2009 Silverado. The first time, the dealer replaced the master cylinder.

The first time I drove it, the brakes failed again. The "good" part is I caused it to happen by replicating the scenario that caused the first failure.

I was sitting on fairly steep hill facing downward. The engine was in auto start. After sitting there a couple minutes, the brake pedal moved a little, the truck started moving, I pushed the pedal harder and the pedal dropped further, followed by the chimes and the service stabilitrack,abs, and traction sys warnings and the loss of power assist.

I limped it to the dealer who is only a couple miles from me while all the codes were current and the dash was still lit up. They still have it.

It will be interesting to see what they do this time. They tell me that nothing is their call on these hybrids. GM tells them what they are going to do.

evois 06-15-2010 09:41 PM

Re: Power Brake Problem?
 
they want to make sure it is done right. hence, usually corporate approval of fixes are made.

xfordguy 06-18-2010 05:03 PM

Re: Power Brake Problem?
 

Originally Posted by evois (Post 223596)
they want to make sure it is done right. hence, usually corporate approval of fixes are made.

I understand and appreciate their rational for corporate oversight on a vehicle with such a complex braking system. I can also see how they can quickly run into lemon law problems though. I'm over 18 days without the truck in just two brake failures, and I don't have it back yet.

Of course, I've got another car that has spent 5 weeks in the shop under warranty so far this year. At least it is back and working now.

xfordguy 06-19-2010 06:01 PM

Re: Power Brake Problem?
 

Originally Posted by 2tall (Post 222711)
gltech, I have been having a similar issue with my 09 Sierra. It didn't start until the dealer installed a software upgrade that was supposed to "fix" a faulty battery charge indicator.
Sometimes while coming to a stop, the truck suddenly lurches as if someone just bumped me from behind. Other times, on takeoff, when the system is in autostop mode, it will hesitate and then lurch ahead, like a car with a faulty autotmatic transmission. I have not noticed any dash lights; the dealer couldn't pull up any codes, and Onstar hasn't reported any diagnostic problems.

I don't know how I missed this on the first pass reading this thread, but my problem started shortly after I took the truck in for the same recall notice and they updated the computer.

evois 06-21-2010 07:51 PM

Re: Power Brake Problem?
 
cleaned. keep it on topic guys!

xfordguy 06-25-2010 03:12 PM

Re: Power Brake Problem?
 
The dealer has been replacing parts as instructed by GM for nearly a month now. They can consistently reproduce the brake failure using the steps I listed above. I takes a minute or two, but they keep failing.

I have a feeling GM is buying a lemon from me very soon.


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