So ever since I've had the car, the abs light in the dash was missing its bulb. I knew this as the light didn't flash on and off upon start up. I finally got a bulb in there a few months ago and I've been trying to diagnose the ABS fault the last 2 weeks. Unfortunately my INPA cable didn't connect to the ABS module, don't know why, but it didn't. Not helpful at all.
First up was the front right abs sensor, diagnosed by testing the actual sensor which was a pain in the ass. Replaced and works.
Secondly I stumbled across a thread about ABS so I followed some of the instructions and decided to diagnose through the ABS module behind the glove box. I came up with the spreadsheet below and started working the pin outs with my multimeter. First the front left abs sensor wasn't giving a reading so I bought and replaced it, then I re-tested, it came back good now so I moved on.
According to the info in the afore mentioned thread and my multimeter, I am not getting power to my ABS module from pins 2, 16 and 33. According to the manual I have, these pin outs are battery voltage ABS relay, plus supply ABS relay and plus supply ABS relay respectively.
Any idea what that means? I think it means that there is a damaged wire between the main ABS relay in the fuse box and the ABS module, but I don't know where to start. I'm not sure if that first resistance reading for the ABS relay is too high or not.
Any advice would be greatly appreciated. I'll continue to search the internets for an answer in the meantime.
Edit: this is the thread I found and used as a reference The definitive guide to self diagnosing your ABS/ASC light. - BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3 | F80/X)