Stuck Brakes 05 tahoe z71

[Wells596]

Having an issue on one I just picked up, all four calipers are sticking and I can't figure it out. The buddy I bought it from said he was towing his boat and felt it struggling and parked it. I've collapsed the calipers by hand completely off the truck but they will not do it while on the truck. Rubber hoses seem to be good. Hydroboost is testing good. Is there something I'm missing? ABS pump possibly bad??

 

[OR VietVet]

Ok, first, welcome to the forum from Oregon.

Second: How do you know ALL FOUR calipers are sticking? Did you lift all 4 wheels/tires off the ground at the same time and all in neutral and you cannot spin the tires by hand? If they are all 4 bound up, then what controls all four at the same time, is something that is like riding around with your foot on the brake all the time. Get a helper. While in the air and engine off, pull the brake pedal up and then see if the wheels still bind. Then try the same with engine running. What are the results? If still binds, then loosen where the hydro-boost and master cylinder bolt together. Not completely unbolt, just loosen to where there is slight separation. do the binding wheels check again. What are the results?

 

[Wells596]

When I drive around the neighbor hood and back to my house all four wheels are smoking at the calipers. I do believe I just figured it out. I pulled both abs module fuses and now the only affected wheels are the rear. Before I couldn't coast down the hill my house sits on now it'll coast to the end of my road about an 1/8th mile.

 

[Wells596]

Ok, first, welcome to the forum from Oregon.

Second: How do you know ALL FOUR calipers are sticking? Did you lift all 4 wheels/tires off the ground at the same time and all in neutral and you cannot spin the tires by hand? If they are all 4 bound up, then what controls all four at the same time, is something that is like riding around with your foot on the brake all the time. Get a helper. While in the air and engine off, pull the brake pedal up and then see if the wheels still bind. Then try the same with engine running. What are the results? If still binds, then loosen where the hydro-boost and master cylinder bolt together. Not completely unbolt, just loosen to where there is slight separation. do the binding wheels check again. What are the results?

If it helps I do have three u1000 codes. One for powertrain, one for airbag and one for body control module.

 

[OR VietVet]

Each specific code will have a diagnostic procedure to follow. The diagnostic process helps you keep from shooting the "parts cannon" at the problem.

I would guess that the codes set after you drove after pulling the fuses? Or were the codes there before pulling fuses?

Any concern you have on any problem you post here, NEEDS the concerns and the attempts made to address them, posted here in chronological order.

 

[Wells596]

Each specific code will have a diagnostic procedure to follow. The diagnostic process helps you keep from shooting the "parts cannon" at the problem.

I would guess that the codes set after you drove after pulling the fuses? Or were the codes there before pulling fuses?

Any concern you have on any problem you post here, NEEDS the concerns and the attempts made to address them, posted here in chronological order.

So with my scanner the only thing it's telling me is u1000 indicates a comm error between system control modules and is often accompanied by other network related u codes. So with how I'm looking at that is the related modules to those specific items are bad. Correct way to look at it or no? I'm trying everything before I resort to just letting the parts cannon go full auto. lol

 

[OR VietVet]

Again, did you get the code(s) after pulling fuses or before? Are you saying the only code you have is u1000 and it is repeated 3 times?

 

[OR VietVet]

Another question, did the buddy or you do any, I mean any, work on the truck before this problem came up? Don't assume. Call the buddy and pin him down and find out.

 

[Wells596]

Another question, did the buddy or you do any, I mean any, work on the truck before this problem came up? Don't assume. Call the buddy and pin him down and find out.

He did do the passenger caliper. All I’ve done is put a set of rear pads on it and try to diagnose the brake issue. Bled them as I thought maybe they didn’t bleed all the air out. Other than that haven’t done anything.

 

[Wells596]

Again, did you get the code(s) after pulling fuses or before? Are you saying the only code you have is u1000 and it is repeated 3 times?

Had the codes before pulling fuses.

 

[Wells596]

 

[OR VietVet]

He did just the passenger side front or rear caliper? Why not both? Was the caliper done for this issue or another issue?

I would look very carefully for any wiring connection problems, corrosion, loose, pins pushed out, etc.... Check all grounds.

 

[rockola1971]

He did do the passenger caliper. All I’ve done is put a set of rear pads on it and try to diagnose the brake issue. Bled them as I thought maybe they didn’t bleed all the air out. Other than that haven’t done anything.

Is "Brake" light on when engine running? Andy ABS messages in message center? How did you bleed the brakes? Do you have a firm brake pedal with engine running? You need a scanner to identify which module(s) are throwing the U1000 code. Me thinks the ABS is a part of it and its no talky which would explain why your brakes arent releasing because you have a solenoid in the ABS manifold not being told to open/close.

 

[Wells596]

Is "Brake" light on when engine running? Andy ABS messages in message center? How did you bleed the brakes? Do you have a firm brake pedal with engine running? You need a scanner to identify which module(s) are throwing the U1000 code. Me thinks the ABS is a part of it and its no talky which would explain why your brakes arent releasing because you have a solenoid in the ABS manifold not being told to open/close.

Not until I pulled both fuses for the ABS. Now I can drive it for about 20ish minutes before they start sticking, I know these things have an issue with solder cracking is that possibly the cause? Thanks for all the help.

 

[rockola1971]

Not until I pulled both fuses for the ABS. Now I can drive it for about 20ish minutes before they start sticking, I know these things have an issue with solder cracking is that possibly the cause? Thanks for all the help.

U1000 is telling you that the PCM is not talking to a module. You need to find out which module it is with a decent scanner.

 

[Wells596]

U1000 is telling you that the PCM is not talking to a module. You need to find out which module it is with a decent scanner.

I've been seeing you guys talk about tech2 scanners. Any reputable place to get it for not a million bucks? Also I'm not sure how familiar you are with the Chrysler world but is it similar to jscan for the jeep world?

 

[rockola1971]

I've been seeing you guys talk about tech2 scanners. Any reputable place to get it for not a million bucks? Also I'm not sure how familiar you are with the Chrysler world but is it similar to jscan for the jeep world?

I got mine on aliexpress around 8yrs ago. Make sure you click on the GM version so the right software comes with it. You can also get a MDI unit which is a emulator of the tech 2 but is connected to a laptop so you dont get a handheld unit with screen like the tech II but you do get bidirectional communication with the 2009+ vehicles. Keep in mind the tech II is only good for GM up to around 2009 model year. Anything else newer requires MDI or equivalent because of protocol changes GM made.

https://www.aliexpress.us/item/3256807395595320.html?spm=a2g0o.productlist.main.21.357f227a99YKsA&algo_pvid=8258ab6e-b336-4aff-9553-0b5b30de0075&algo_exp_id=8258ab6e-b336-4aff-9553-0b5b30de0075-10&pdp_npi=4%40dis%21USD%21416.59%21291.61%21%21%212899.00%212029.30%21%402101fb0a17275632965573105e9fd5%2112000041381517807%21sea%21US%210%21ABX&curPageLogUid=bNzFLJKlga7o&utparam-url=scene%3Asearch%7Cquery_from%3A

The Tech II is what GM service techs would use on your 2009 and older vehicles at the dealership. It is way much more than a regular old scanner. It is bi directional which means it can read AND write/control. For instance you hook up and turn fuel injectors on/off individually for troubleshooting. Operate a certain HVAC door motor for troubleshooting. Bypass a safety in your AC for troubleshooting. Even erase the current security code on your factory radio and default to 0000 which comes in handy if you have to pickup a junkyard replacement. It will also flash a GM program to your BCM, PCM, etc. You have to buy the license for it which is cheap enough. The tech 2 pays for itself in one day of working on your vehicle. I paid around $300 for mine.

*NOTE* The newer MDI unit is backwards compatible with pre 2009 vehicles also.