AT4 service brake assist

[rmkmb]

Got truck back today,look like its fixed for now,the same update according to the dealer  fixes also the brake pad life issue as there is only one update on the sheet .

 

[Therickyp]

I have a Custom Trail Boss and the service brake assist came on at about 700 miles. The dealership fixed but 1,200 later it came back on. I’m so pissed. I don’t want my family in my truck now. I’ve owned a 2017 and 2018 and I never had any problems with those trucks. 

[Maverick0984]

It's a totally different error but thought I'd add the issues I've already had on my 5.3L AT4 with ~250 miles on, purchased 2 weeks ago.  3 Days (maybe 100 miles) in the display on the radio went out, wouldn't come back on no matter what I did.  Dealer had it for 4-5 days (including weekend) replacing the radio? like seriously? during that time GM's servers were down and they were unable to program it correctly so lost 2 days just waiting on that nonsense.

 

Then yesterday, service light went on but no messages otherwise other than the email from Onstar telling me there's an engine or transmission issue.  Took it in this morning and and they had to replace a power supply that powers a device that monitors other sensors and instruments. 

 

The dealer has been good about it, insisted in giving me a Denali loaner the first time before we knew it'd be several days and this last one I just waited in the waiting room but jeez.  I've had it in the shop for nearly as long as it's been in my garage since I purchased it.

 

I'm still getting an odd flicker on startup in the main dash screen behind the steering wheel.  Anyone else have that? It might be nothing but my tech background makes it seem like it's something failing.  I actually thought a bad power supply could cause it but it remains after they replaced that.

[eppieguy]

1 hour ago, Maverick0984 said:

It's a totally different error but thought I'd add the issues I've already had on my 5.3L AT4 with ~250 miles on, purchased 2 weeks ago.  3 Days (maybe 100 miles) in the display on the radio went out, wouldn't come back on no matter what I did.  Dealer had it for 4-5 days (including weekend) replacing the radio? like seriously? during that time GM's servers were down and they were unable to program it correctly so lost 2 days just waiting on that nonsense.

 

Then yesterday, service light went on but no messages otherwise other than the email from Onstar telling me there's an engine or transmission issue.  Took it in this morning and and they had to replace a power supply that powers a device that monitors other sensors and instruments. 

 

The dealer has been good about it, insisted in giving me a Denali loaner the first time before we knew it'd be several days and this last one I just waited in the waiting room but jeez.  I've had it in the shop for nearly as long as it's been in my garage since I purchased it.

 

I'm still getting an odd flicker on startup in the main dash screen behind the steering wheel.  Anyone else have that? It might be nothing but my tech background makes it seem like it's something failing.  I actually thought a bad power supply could cause it but it remains after they replaced that.

I’ve got the same flicker, the dealer replaced the cluster. Didn’t fix it, software update, didn’t fix it, they have now opened a “TAC” case with GM a few months ago and they have no updates as of last week. 

[Maverick0984]

43 minutes ago, eppieguy said:

I’ve got the same flicker, the dealer replaced the cluster. Didn’t fix it, software update, didn’t fix it, they have now opened a “TAC” case with GM a few months ago and they have no updates as of last week. 

Thanks. That makes me feel better I'm not the only one but also worse that they don't know how to fix it.

[Sin City Trail Boss]

Does anyone know if the braking issues have been permanently fixed now? I mean this problem has been around for a while now, wonder if GM finally got it worked out. I got 2,300 miles on my Custom TB, and so far no issues (thank god) but this scares me.

[eppieguy]

9 hours ago, Sin City Trail Boss said:

Does anyone know if the braking issues have been permanently fixed now? I mean this problem has been around for a while now, wonder if GM finally got it worked out. I got 2,300 miles on my Custom TB, and so far no issues (thank god) but this scares me.

I really can't answer your question but what I hope I can do is lesson the scare you have with this possible issue. I had it happen to me and the short story is that you lose the power assist, you don't lose brakes, it may surprise you and you will have to push on the peddle harder to get it to stop but you can stop it without a lot of effort. I am by no means trying to say that this isn't a safety issue because it is, but all I'm saying is you "Don't lose your brakes", it sounds a lot worse than it actually is. If these trucks actually lost their brakes there would be a recall, not a TSB on it. I hope this helps.

[Maverick0984]

 

15 hours ago, eppieguy said:

I’ve got the same flicker, the dealer replaced the cluster. Didn’t fix it, software update, didn’t fix it, they have now opened a “TAC” case with GM a few months ago and they have no updates as of last week. 

Looks like a Bulletin was recently released.  Unfortunately I don't have a subscription here so can't get more information about it.

 

I'm hesitant to spend $15 on something that might say nothing other than that GM is aware of it.

 

https://www.repairprocedures.com/service-bulletin/document/2019/gmc-truck/sierra-1500-new-model-4wd/preliminary-information/pic6370/100309083_13131286_2_82_0_5388086.html

[eppieguy]

32 minutes ago, Maverick0984 said:

 

Looks like a Bulletin was recently released.  Unfortunately I don't have a subscription here so can't get more information about it.

 

I'm hesitant to spend $15 on something that might say nothing other than that GM is aware of it.

 

https://www.repairprocedures.com/service-bulletin/document/2019/gmc-truck/sierra-1500-new-model-4wd/preliminary-information/pic6370/100309083_13131286_2_82_0_5388086.html

Thanks, I just e-mailed this to my dealer, I'll let you know what they say.

[eppieguy]

I just heard back from my dealer, this is the response I got,

 

"I just looked up the document number.  It states that if customer is experiencing flickering on the screen not to perform any 

repairs at this time.  Document say that GM is working on repair for concern at this time. 

So hopefully they come out with repair soon."  

[Maverick0984]

2 hours ago, eppieguy said:

I just heard back from my dealer, this is the response I got,

 

"I just looked up the document number.  It states that if customer is experiencing flickering on the screen not to perform any 

repairs at this time.  Document say that GM is working on repair for concern at this time. 

So hopefully they come out with repair soon."  

Seems to be a lot of issues with this sort of response unfortunately.  "GM is aware, but no fix yet."

 

Thanks for passing the info along though.  Means I won't ask about it for a while.

[1997SierraSLT]

On 8/8/2019 at 8:51 AM, eppieguy said:

I really can't answer your question but what I hope I can do is lesson the scare you have with this possible issue. I had it happen to me and the short story is that you lose the power assist, you don't lose brakes, it may surprise you and you will have to push on the peddle harder to get it to stop but you can stop it without a lot of effort. I am by no means trying to say that this isn't a safety issue because it is, but all I'm saying is you "Don't lose your brakes", it sounds a lot worse than it actually is. If these trucks actually lost their brakes there would be a recall, not a TSB on it. I hope this helps.

Makes you feel confident to load up the family, hook up the travel trailer and take a scenic drive through the mountains for a nice little vacation.

[Robert95]

Just bought a RST truck the second week of August and have about 670 miles and I just got the brake system failure, just turned my truck off after I drove to get hoke then turned it back on brakes work now but engine light is still on

[batman900]

40 minutes ago, Robert95 said:

Just bought a RST truck the second week of August and have about 670 miles and I just got the brake system failure, just turned my truck off after I drove to get hoke then turned it back on brakes work now but engine light is still on

Good lord. Like seriously, if your talking to the engineering team and telling them, yeah we can cheap out here here and here, don't spend much time on this this and this..... but lets make sure we get this one thing right........ That one thing should be the damn brakes! 

 

[ricktesh]

i had the same issue and was told by the dealer/service department it was caused by remotely starting my car via the my gmc app.