bmwtmx

I just purchased my first 968 so I am a new member of the club. Very happy indeed. The car has some small issues and I would like to tackle them all so I am going to start with the first one. The previous owner told me that he purchased a new battery that was the wrong size and brought the car back to the shop to have the correct battery installed. Upon installing the battery he said that he saw sparks under the hood when the mechanic tried to hook it up. After that the ABS light came on and has never turned off. Any suggestions on how to troubleshoot this problem would be appreciated. I am a pretty good (eh!) mechanic and I have a scissor lift in my garage so I have access. I just am not sure how to proceed.

PaulD_944S2

Do a quick search for "Clark's Garage" and click on Garage Shop Manual.
http://www.clarks-garage.com/

In the red banner that says Body, top of the list are two links to airbag testing and resetting.

Try the Airbag Warning Light Reset method first before troubleshooting, it may simply be a set fault code.

bmwtmx

Thanks but this is an anti-lock brake issue. Not airbag. But I have been searching and shall see.

Jay Wellwood

I'd check the continuity of the wheel pickup sensors first.

PaulD_944S2

You're right, sorry about that!
Here's a site link regarding ABS diagnosis:

https://rennlist.com/forums/924-931-...d-working.html

Basically, start by testing the sensors and wiring from the ABS control unit in the right of the passenger side footwell.

djantlive

try replacing the abs relay. It's easy and fairly cheap

bmwtmx

Will be working on it next week so I will be testing a few things out. Not sure why the battery would cause this but lets see what I find. Will update.

bmwtmx

Turns out a negative lead to the battery was not hooked up when the previous owner had a new battery installed. ABS light is off! How silly.