Accessing the ABS Module - procedure
Thread Starter
Drifting
Joined: Aug 2009
Posts: 1,972
Likes: 243
Accessing the ABS Module - procedure
I searched, I read the FAQ, Tech Tips just can't seem to locate it. Maybe I completely eyed over it because I know months back I had found it easily.
I'm installing a DRM Brake Bias spring soon. After the installation and bleeding I do want to check to see if there are any ABS codes stored.
I read a thread somewhere a ways back about how a few ABS codes were causing a guy some 'hard brake pedal' issues. A clearing of the codes cured him. My brakes aren't too hard but it depends what you want to compare them to - and if I'm comparing them to my other car or my truck, then ya the Vette brakes are HARD to push.
So it seems easy enough to go through the modules and check on your ABS - if you got the procedure that is. And I don't.
The car is a 1994 LT1/ZF6, which makes it OBD I and it has the OBD II style connector. I do have an AKM cable and some software but I believe going through the modules is done entirely via the DIC buttons and the LCD screen in the dash.
Your help and guidance is appreciated!
I'm installing a DRM Brake Bias spring soon. After the installation and bleeding I do want to check to see if there are any ABS codes stored.
I read a thread somewhere a ways back about how a few ABS codes were causing a guy some 'hard brake pedal' issues. A clearing of the codes cured him. My brakes aren't too hard but it depends what you want to compare them to - and if I'm comparing them to my other car or my truck, then ya the Vette brakes are HARD to push.
So it seems easy enough to go through the modules and check on your ABS - if you got the procedure that is. And I don't.
The car is a 1994 LT1/ZF6, which makes it OBD I and it has the OBD II style connector. I do have an AKM cable and some software but I believe going through the modules is done entirely via the DIC buttons and the LCD screen in the dash.
Your help and guidance is appreciated!
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
Thread Starter
Drifting
Joined: Aug 2009
Posts: 1,972
Likes: 243
Thanks for the link...
By reading I determined that I needed to short pin 12 to pin 4, which I did, then keyed on (didn't start).
This appears to have worked and it went into a diagnostic mode.
Here is what I found:
Module 1: Code H53
Module 4: No Codes
Module 9: No Codes
From what I read, I believe module 1 is the ccm and code H53 is a VATS issue. Makes sense since last summer I had two VATS related NO START issues. I never did anything to resolve, other than waiting 5 minutes and trying again. Each time it worked and it started right up. I may disable VATS via a reprogram.
Module 4, PCM - no codes, good!
Module 9, ABS - no codes, good!
So, this leads me to believe there is no fault with my ABS.
What I don't understand is how to navigate the modules, or what buttons on the DIC do what, and what useful info is in there anyway. It seems just ground pin 12 to pin 4 allows essential scrolls through any error codes on the LCD screen.
By reading I determined that I needed to short pin 12 to pin 4, which I did, then keyed on (didn't start).
This appears to have worked and it went into a diagnostic mode.
Here is what I found:
Module 1: Code H53
Module 4: No Codes
Module 9: No Codes
From what I read, I believe module 1 is the ccm and code H53 is a VATS issue. Makes sense since last summer I had two VATS related NO START issues. I never did anything to resolve, other than waiting 5 minutes and trying again. Each time it worked and it started right up. I may disable VATS via a reprogram.
Module 4, PCM - no codes, good!
Module 9, ABS - no codes, good!
So, this leads me to believe there is no fault with my ABS.
What I don't understand is how to navigate the modules, or what buttons on the DIC do what, and what useful info is in there anyway. It seems just ground pin 12 to pin 4 allows essential scrolls through any error codes on the LCD screen.
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
You missed this part of the article???
While all C4 antilock systems have on-board diagnostic capability, with ABS-2, there's a catch: its only "kinda-sorta on-board" because fault data cannot be read directly. A unique electronic device, the "ABS Tester" (PN J-35890), is required to translate fault data from '86-'89 EBCMs into information useable by those attempting to diagnose the system. Whoever at GM allowed Bosch to get away with this should have been fired-or at least transferred to the Cobalt trunk interior trim group. This gets worse. Today, J-35890s are virtually nonexistent so, unless you run across an ABS Tester on eBay Motors; in a practical sense, other than the "Antilock" warning light coming on when there's a problem, any on-board diagnostic ability ABS-2 has is useless. Nevertheless, there are diagnostic procedures DIYs can use to solve the most common problems.
Thread Starter
Drifting
Joined: Aug 2009
Posts: 1,972
Likes: 243
No, but I read this:
"is required to translate fault data from '86-'89 EBCMs into information useable by those attempting to diagnose the system."
and interpretted it as that applied to 86-89. I believe somewhere in the article is mentioned that 90+ had more capabilities through the LCD screen. I don't believe the article got into how to navigate through the modules. I know hitting some of the buttons on the DIC changed what I saw on the dash but I can't say I knew what it meant. I have the FSM and I'll check to see if there is any pertinent information in there.
"is required to translate fault data from '86-'89 EBCMs into information useable by those attempting to diagnose the system."
and interpretted it as that applied to 86-89. I believe somewhere in the article is mentioned that 90+ had more capabilities through the LCD screen. I don't believe the article got into how to navigate through the modules. I know hitting some of the buttons on the DIC changed what I saw on the dash but I can't say I knew what it meant. I have the FSM and I'll check to see if there is any pertinent information in there.
