G.P.sVette

This is 96 Auto convertible. I have done the code reading/clearing method with pins 4/12 shorted and using the dash buttons to scroll through modules ( only have 1 and 9 plus A). The ASR/ABS warnings stay on the drivers info screen all the time.
When in the diag mode, speedo screen show no codes "C12" then cycles through the modules, 1="- - -", and then 9=ERR. I can't find any threads referencing this issue. Using the buttons, I get module 9 to display and scroll to 9.7 and clear but the warnings never extinguish. Its like the car doesn't see the ABS system.

The car has not had good braking (takes alot of brake pedal pressure to stop car) for some time and I have very little repair history, other than fuel pump and alternator replaced.
Getting FSM soon as I can.


My questions;
1. Where is the ABS module. I need to check connections and ground if it has one.
2. What is the rectangular finned silver unit at top of drivers side firewall The tag shows SERV.NO. 16214399 BSCX and 86BSCXKK260721C6L. (Not sure if this is relevant but want to know what that is)

Thanks.
Jim

bac22

At least in the coupe (not familiar with verts) the ABS module behind driver seat in compartment, basically opposite side of the storage bin where jack is stored. My guess is the ABS module is foo or connectors have a problem. I actually found a @#$% mouse living in that compartment once when I was have some trouble, though my problem was different from yours.

The finned silver unit is the ECM of the car, doubtful that will be the problem. The ABS module communicates with the CCM module to activate the light...others will tend to refer to it as the BCM as well, though GM reference it as CCM in the field service manuals.

G.P.sVette

Update; Checked the ABS fuse and the CCM fuse, both good. Disconnected battery (at least 30 mins) and removed all ABS module cables, cleaned all on both cable and module sides. Still have same ASR/ABS indications. Looking for any service book tomorrow, hope it references this module 9 ERR in diag mode.

As for poor braking, I will power bleed the system this weekend. Regular method didn't do much even though some air was removed. The pedal will pump up with engine off, but goes mushy when started up.

Any advice on above is appreciated.
Thanks.
Jim

WVZR-1

The "ERR" is displayed anytime that there's an issue with the CCM communicating with the module selected. In your case the CCM isn't communicating with the ABS/TCS. I don't believe that EBTCM codes/issues can be cleared by disconnection of the battery. Scanner or 100th ignition cycle key for a particular DTC.

I believe there's 2 under-hood fuses related to ABS/TCS (ABS & BRAKE HYDRAULICS) - FUSE BOX 1 - Until yesterday I didn't know how those under-hood boxes were labeled.

G.P.sVette

Update: Checked both fuses. Good. Pulled ABS power cables and measure some voltages. With key on,the black connector had 12v on both green wires and the blue wire, 0v on the other one. White connector as follows, clockwise from key
Blue-0v
Brn/Wht-12v
Grn-.05v
Red-05v
Vio/Wht-12v
Slt/Wht-.05v
Blk/Wht-.05v
Vio-12v
Brn-5v

Not sure what all this means without FSM but all the alarm indications were gone. Of course they came back when I reconnected system.
Suppose I can just leave the connectors off and deal with the blinking "sys" on the speedo screen. I drive the car hard.

Power bleeding went ok (I haven"t done this before) but never got a steady clear flow without bubbles from either front wheels. So not sure what that means. Pedal bout the same (not running) and the test drive was about the same too.

Need a direction. Master cylinder? pull everything loose and purge all the lines? drop the calipers verify the pistons are free?

Any more advice out there??
Thanks

bac22

See if this gets you on the right track, I scanned via my phone a few pages from FSM.
https://1drv.ms/b/s!AlcEDrQPebO_ghNLcocScDzI5Crx

I'm leaning towards bad EBTCM. You should also consider picking up a set of FSM, they are worth it when trying to troubleshoot these types of problems.

G.P.sVette

Update: The drawings were very helpful, another fuse eng 2 was the problem. replaced and DIC is clear of ABS/ASR warnings. I thought I had checked all those fuses but guess not. I have a couple test drives on the new fuse..haven't done an emergency stop yet..but will soon. Once I get the pedal to feel normal.

Appreciate the kick backs on this. Especially "bac22".

Oh, the FSMs are in route, got em on "books4cars.com", used (hopefully not to much).
Closing this thread. Fixed it

G.P.sVette

Thks