dsnorth2

Can not find any info on why is it neccessary to disconnect the battery when doing a brake job on a 2022 . Can anyone answer this for me.

WhiteDevil828

The reason is so the car won’t go into brake self check mode. From what I’ve read the computer will periodically test or adjust the pistons and create issues with your brake system or it can possibly injure you.

mikegr

Yes if brakes activate for self check for any reason and the calipers are off the rotors, it can push the pistons out of the calipers or worse if your fingers are in the way somewhere.

Ricketts

I absolutely recommend disconnecting battery due to possible brake system self test happening. You surely don't want that happening during.

hamta

Agree on all of the above with disconnecting the battery. I've done 2 brake changes on the C8 (mine and one of my neighbors) and disconnected the battery. The only re-programming that each car required was re-indexing the windows which took about 5 seconds each car. All other programming was saved.

EC145Pilot

Not only the self test, but, let's say your original pads are worn down, you get new pads and in order to put them in you use a tool to spread the pistons, slide the new pads in, finish the job, get in the car, start the car and push on the brake pedal, It will go down and codes will happen and warnings that your ABS needs service and limited to a ridiculously low speed.
To reset all that, it necessitates knowledge of how to reset the system and the lights (gotta have a device to plug in to do some of that), or a trip to the dealer.
So, to prevent all that, disconnect the battery, do the brake job and before you reconnect the battery, pump the brake pedal to set the pistons against the pads. If all went well, when you reconnect the battery and start the car, the only thing you will need to do is index the windows and bed in the new pads.

mikegr

curious how common the issue you describe with the brake pedal is. I have swapped pads about 20 times and changed out front for AP Racing kit and have never pumped the brake pedal before reconnecting the battery. I step on brake before starting car then pump brakes and have never seen a code. I could just be lucky though.

EC145Pilot

I haven't done a search of the Forum but remember reading several have had this issue.
I think it has a lot to do with pushing the pistons in for new pads and not seating the pistons against the new pads before starting the car. You are lucky or it could be you state you step replaced(assume push) the pedal before starting the car.
If you don't push the pistons in then it may not be an issue.
I've replaced several times on on '21 and '24 and have always disconnected the battery, but did forget, one time, to set the pistons prior to connecting the battery, started the car, pushing on the brake pedal and got the lights and message and the ABS module was making clicking sounds. I think the codes/messages/lights come on because the ABS module sees a large movement that is out of paratmeters.

To reset the brake message and reset the module:
1. without stepping on the brake pedal, push the start button for about 10 seconds, power will be applied to all the systems, release the start button.
2. push the brake pedal all the way to the floor, do not push the start button. Hold the brake pedal until the warnings and the ABS messages go away. Someone posted once that this takes about 30 seconds. You will still have a check engine light, which can be reset with a good OBDII reader, Creader Elite for GM, or the dealer can do it.

Chevrolet recommends disconnecting the battery.