mellor_21

Hey all,

So I finished putting my car back together after having to do a full rebuild on the engine, and everything seems to be going well except:
My ABS and Brake light are both permanently on. They both come on about a second after starting the engine.
I used a scan tool from Autozone and stopped by a small local shop, but both were completely unable to connect to the ABS system.
I'm thinking I may have a bad ground? But thought I'd see if you guys had any advice on where to start looking. I've gone over the whole thing myself but can't see anything obviously wrong.

Also, I've tried searching but couldn't figure out good search terms; everything returned guides based on specific ABS codes and such. Couldn't find anything related to the ABS (ECBM?) just straight up not responding.


Oh, by the way it's a 2001 WS6 Trans AM

FirstYrLS1Z

iTrader: (4)

'both were completely unable to connect to the ABS system', do you mean the OBDII port wouldn't indicate anything,not even emission monitors readiness ?

mellor_21

The OBDII port was working for everything except for ABS. Once you select ABS it tries to connect for few minutes then fails.

If it helps, my fans were also not working. I wired in a manual switch for them for now but that's a large reason I'm suspecting a bad ground or a wiring issue.
Is there a ground that they both share?

mellor_21

. .

Floorman279

iTrader: (11)

Try disconnecting the abs module and cleaning the connections

WD10

Did you check your fuses? There are 3 fuses under the hood also you have 2 grounds going the the module.

mellor_21

https://ls1tech.com/forums/suspensio...l#post16590926

I'll give that a shot, but would you suspect that after just reinstalling the motor? It was never taken apart is why I ask

I've checked the fuses and the three relays, all good.
Which grounds go to it? Do you know if either of them are shared by the fans?

WD10

G108 at top left radiator support and G102 left front shock tower. Yes the G108 also grounds the fan motor.

Floorman279

iTrader: (11)

yea dont remove the module just the connectors. i would think if it was a ground issue you would also have a service vehicle light and brake light on. i delete my abs and since that connector is no longer connected i get all those on. i would think a bad ground would **** off the entire system not just those 2 lights.

mellor_21

Brake light is on. Service vehicle also is, I didn't realize that would play a part, just assumed it was due to my exhaust leak. Sorry I should've mentioned that.

This 100% sounds like the issue, thanks!!
I'll see if I can hunt down which one that is. I don't remember one on the radiator support so I'm sure it's tied in in the wrong spot somewhere

By left you mean driver's side, right?

Also, I'm seeing elsewhere that that's marked G106, was that a typo or was it just marked different on different models? (camaro vs firebird for example)

WD10

Yes Drivers side. The info I seen stated G108 in one place but else where it states G106. Just follow the ground (black wire) from the fan and it should lead you to it should be easy. Possibly there are separate wires bolted together there.

mellor_21

So this guy here, right?

Only difference on mine is that it has a separate cable going to the headlights. Both cables using it are testing at 0 ohms to the other grounds and to the ground post on the battery, so I guess it's good.

Would you suggest checking the grounds from the fan plugs next?

Also, the braided ground right below this one is a bit frayed and soaked in oil/power steering/etc from leaks I've had in the past, would you suspect anything being wrong with it causing issues on ABS and fans? I tested it as well and was showing 0 ohms, but didn't get under the car to test the other end (which I believe is on the side of the block right behind the motor mount and above the o2 sensor connection, right?) Although I assume I'd be having a few more issues if that one wasn't working..

WD10

Yes that is where it is bolted to.I think it should be 2 wires bolted there if you can not find another wire follow the wire into the harness to where it splices with many wires it is possible the splice is the problem.

landstuhltaylor

iTrader: (6)

The scanners at Autozone can't read your ABS module. You need a different scanner

mellor_21

I tried one from a shop with the same result.

I found the problem while fixing an ignition issue this morning... (Ign problem started yesterday afternoon)



(picture seems to be broken? idk shows up in edit but not in main thread for me.. anywhere here's a link to it https://i.imgur.com/clGmXcL.jpg )

The ign abs fuse wasn't showing resistance till the engine warmed up. My phone's camera is a potato but if you look closely should be able to see the tiny gap on that fuse.

Replacing that solved both problems. I've never seen a fuse with such a small break, is that common? I was still reading 9 ohms across that gap

Thanks for all of the help everyone I really appreciate it!

sjsingle1

iTrader: (1)

isnt the TECH2 scanner the only tool that can read ABS ?? jus sayin....

mellor_21

I was actually curious if that was the case.
Everything's gravy now though. Just need to fix exhaust leaks to get rid of the o2 sensor codes.

Thanks again for the help everyone!

2QuikTA