Check stability, service break booster

[Zburhop]

Hi,
I just baught a 2004 Yukon xl. The guy I got it from staid the break booster failed and he had put a new one in. He showed me the brand new part. But eventually the dash light started coming on with “ check stability, service break booster” breaks feel completely fine. Where should I start. Google results have said anything from a bad heel sensor, bad abs module, to poor engine block grounding. Not sure which angle to peruse.

 

[wjburken]

Hi,
I just baught a 2004 Yukon xl. The guy I got it from staid the break booster failed and he had put a new one in. He showed me the brand new part. But eventually the dash light started coming on with “ check stability, service break booster” breaks feel completely fine. Where should I start. Google results have said anything from a bad heel sensor, bad abs module, to poor engine block grounding. Not sure which angle to peruse.

I would start by getting the codes off of your vehicle that are behind the message on your dash.

You will likely need one that can read ABS codes. Autozone should be able to do this for free. Just make sure you get a printout of the codes so you can share them here.

 

[Zburhop]

I would start by getting the codes off of your vehicle that are behind the message on your dash.

You will likely need one that can read ABS codes. Autozone should be able to do this for free. Just make sure you get a printout of the codes so you can share them here.

I’ll do that! I thought this error dident show codes...... could it be a simple as the guy before me not having the codes cleared?

 

[OR VietVet]

Yes, it can be that simple but also the code(s), I think, are supposed to clear themselves after so many key cycles if there is no problem but that may be on newer models. Someone here will know for sure.

 

[wjburken]

I’ll do that! I thought this error dident show codes...... could it be a simple as the guy before me not having the codes cleared?

What is the timing of the error message showing up? Was the error message present when you bought the truck or did it show up later? If it showed up later, I would bet he cleared the codes but you still have an issue. If it was there when you bought the truck it could be because the guy didn’t clear the codes, but I wouldn’t count on it.

Get the codes and share them and see where things go from there.

 

[dnt1010]

If the previous owner replaced the part between the brake reservoir and firewall that does not supply the power boost. On these Hydro-Boost systems the boost is a function of the ABS system. I think you may find the ABS assembly underneath along the drivers side frame rail or under the hood, I am not sure on a 2004. Most likely you have a bad ABS control module but you really need the ABS codes to narrow it down. You will probably lose power boost soon if you do not do the repair. I hate it when an owner sells a vehicle knowing it has a problem without disclosing it, especially on a critical system such as brakes. Attorneys love guys like this.

 

[Zburhop]

So I’m going to get the codes but I think I found the problem and I want to run it by you guys to see if you agree. I took the dash off to repair some wiring and saw that the instrument cluster is missing all of its bolts. It’s just sitting in the dash. That leads me to believe that it’s been taken out and or replaced. Then I found this post and gm bulletin. https://www.justanswer.com/chevy/2yob6-speedo-fixed-display-reads-service-brake-booster.html

It basically says that an instrument cluster has to be programmed to the truck. Apparently if it is not done the device thinks it is looking for a system present on trucks with rear disk breaks.(Mine has rear drum breaks) And if it does not have this system It sends back the service brake booster code. So it sounds to me like the unit was replaced... which also leads to to believe that the mileage may not be correct. Does this seem logical?

 

[wjburken]

So I’m going to get the codes but I think I found the problem and I want to run it by you guys to see if you agree. I took the dash off to repair some wiring and saw that the instrument cluster is missing all of its bolts. It’s just sitting in the dash. That leads me to believe that it’s been taken out and or replaced. Then I found this post and gm bulletin. https://www.justanswer.com/chevy/2yob6-speedo-fixed-display-reads-service-brake-booster.html

It basically says that an instrument cluster has to be programmed to the truck. Apparently if it is not done the device thinks it is looking for a system present on trucks with rear disk breaks.(Mine has rear drum breaks) And if it does not have this system It sends back the service brake booster code. So it sounds to me like the unit was replaced... which also leads to to believe that the mileage may not be correct. Does this seem logical?

@alaska_guy?

 

[OR VietVet]

You may well be on to something. Sounds more and more like this rig was just patched together to sell and that was it. Do you have a Tech 2?

 

[Zburhop]

So I’m going to get the codes but I think I found the problem and I want to run it by you guys to see if you agree. I took the dash off to repair some wiring and saw that the instrument cluster is missing all of its bolts. It’s just sitting in the dash. That leads me to believe that it’s been taken out and or replaced. Then I found this post and gm bulletin. https://www.justanswer.com/chevy/2yob6-speedo-fixed-display-reads-service-brake-booster.html

It basically says that an instrument cluster has to be programmed to the truck. Apparently if it is not done the device thinks it is looking for a system present on trucks with rear disk breaks.(Mine has rear drum breaks) And if it does not have this system It sends back the service brake booster code. So it sounds to me like the unit was replaced... which also leads to to believe that the mileage may not be correct. Does this seem logical?

so I confirmed I do have hydraboost. It looks like I should not be recieving “service brake booster” with that system. But I’m also recieving “service stability”