2012 C6 GS - Basically Bone Stock (well not quite - but pretty darn close).

I have been fighting a Communication Problem for a while now. I have been working with a local mechanic who is a friend, and his Scan Tool is telling him that it's lost communication with the ABS module.

I just purchased a new ABS module from an Internet GM dealer I am planning to install it tomorrow.

My question is - Will it need to be "programmed" to the car ?

If so - will the car be driveable without a reflash (meaning will I be able to drive it to a local dealer to get the module flashed) ?? I don't care if the ABS or even the speedo doesn't work - as long as the car runs / drives OK....

 

Well if ur not changing in the parking lot of the dealer what does it matter?? don't work tow, u have no other options. U will have air in the system so thercaily brakes should not work expert ebreak so that in opinion hazard go very slow.

 

Don't think you need to do anything but replace the EBCM, just disconnect your battery before removal. Is it safe to assume that you have previously disconnected the wiring harness connecting the EBCM to look for and clean up any corrosion or bent/recessed connector pins when you tried to resolve the original problem? That may have been the problem with the EBCM communication failure and if the connector is the problem, will follow with the replacement as well.

Good luck & hope this corrects your problem.

GD

 

I'm just changing the ABS Module - you can do that without toughing the hydraulic portion of the system, so as long as the issue was not the hydraulic portion of the unit "leaking" into the electronic part of the unit - all should be OK.

 

Very safe to assume that big multi-pin connector has been off before.. More than once. The second time it came apart - I sprayed a good bit of contact cleaner onto both the male & female connectors, and the problem persists.

Everything "Looked" fine, both to me and to the pro (Independent) mechanic that was helping me - and based on the way it's acting - my bet is that if the module is bad - there is an intermittent issue on the board of the ABS unit.

 

If you have a no comm with the ABS and your mechanic/friend has not checked the ABS power and grounds you may be replacing a perfectly good module…has he done that ????

 

So - it seems that the issue is not NO Communication with the ABS unit - but rather intermittent communication. And once you lose communication - it sets the ABS / Traction control / Active Handling System messages, and the Check Engine light and the brake light.

Yes - we did look at power and grounds. I can't tell you I cleaned up every ground on the car - but I cleaned up a bunch of them, and that didn't seem to help.

Swapped out the Module this afternoon, and while the car was driveable - it appears that the new ABS module needs to be programmed to the car. The Pro grade scan tool was able to see the wheel speed sensors - so there is some communication - but not enough...

 

You have to clean the ground applicable to the EBCM…cleaning every ground won’t help if it’s not the correct one. You either have communication or you don’t !!…if you go to the EBCM with your scan tool and look at live data and see data PIDS you have communication…is the only data you see wheel speed sensors ??…there should be more !!

 

Understood. I think I'm going to need to et the ABS Module programmed. Hopefully - that will resolve the problem - if not - then (and after I sober up) - I'll get out the Tech II and see what I see coming off the ABS computrer....

More to follow...

 

Just following up. I did need to get the ABS module programmed, and I had the PCM reflashed while I was at it (it was also a replacement PCM, one that was supposedly - programmed to my VIN" by an "indie seller"). That resolved a couple of the issues - and it verified that I now had communication with the ABS module, but I still had a ABS light, a Traction control light, and DIC messages. (But no check engine light or brake warning light anymore).

However - after that work - the car would sometimes be hard to get to crank over, and hard to shift into gear - both of which require the brake pedal to be pressed. I also noticed that after a start - the ABS & Traction Control lights were off, but they would come back on after my first stop. This led me to (actually I paid my Independent mechanic to) change the brake pedal sensor - the thing has a freaking 6 pin connector on it. The old sensor came off in multiple pieces. New sensor in - ABS & Traction control lights were off, but came back on after a few mile drive, did the cal with the Tech II, and the problem seems to finally be cured. I just got it through NJ inspection today - after all but one of the IM monitors finally reset (NJ will let you pass with one IM Monitor not ready).

So - Yes - I fired the parts cannon at it... Replacement (used) PCM, replacement ABS module, and replacement brake pedal sensor. Hopefully - that's all for a while...

THANKS everyone for the help & suggestions !!!!