people post before about this ABS light/brake light/ESP light issue and found lots of different suggestions when searching the archives - I have never seen a fix for it and thought I'd share my experience and how I fixed it (many, many thanks to WindyCityS4 for his time and help)...

About 10 days ago, I was making a left turn and my ABS light came on, brake light started flashing and the ESP light came on - this was followed by 3 loud beeps. First, I checked the brake fluid level as some have suggested - it was fine.

A VAG-COM scan of the ABS system showed fault the code '00257, ABS inlet valve (N101), front left, 35-10'.....so, Bentley says there are 3 things to check.

1. the ABS controller itself (under the back seat)

2. the valve itself (there is a procedure for checking this in Bentley as well)

3. the wiring to the ABS controller

I put a different ABS controller in, same code. I then looked into the wiring. There is a nice description of how to check wiring to the ABS controller in Bentley - basically, you need to check resistance between different pins in the harness going to the ABS controller - Bentley gives the correct #'s to look for (there are ~50 different pins)...

As it turns out, I was supposed to see 9-22ohms between pins 5+3 on the ABS controller wiring harness - there was none! (Pin 5 actually is the pin going to the ABS inlet valve, N101)....

Resistance between all other pins (as descibed in Bentley) was within spec.

Anyway, we pulled the wiring harness going to the ABS pump and found many wires - one of which was the same wire that was supposed to go to pin 5 of the ABS controller harness. Continuity was checked for a number of different wires and found to be fine in all wires, except, the one in question.

Well, I have NO idea how this particular wire could have been cut/crimped/destroyed but somehow it was.

We basically ran a wire from the correct position on the harness going to the ABS pump back to the harness going to the ABS controller and - voila - it was fixed!!!!

(I took some pics but don't have my camera with me right now)

I've also come across posts where people have had their ABS controller replaced without success (an approx. $1000 part) - perhaps some people are having a similar wiring problem.

Again, I have no clue how the wire broke or where the break was (it is really hard to trace all those wires - you'll see if you look under the back seat).

Just a few suggestions if you decide to try to check this out on your car:

You obvioulsy need a VAG-COM to check for ABS codes to give you some guidance on where to start looking.

You need to have the procedure to re-code the ABS controller soft code and reset the steering angle sensor which somehow gets messed up when you remove the ABS controller - I have the procedure if you need it (just not in front of me at the moment).

Bentley was needed to see which pins meant what in the ABS controller wiring harness and to tell you which pins to check resistance between and which pins to jump with which pins if you decide to run a check on the ABS inlet valves themselves.

I guess I was lucky to find that the wire in question was located in an easy to get to spot.....

I'm out of warranty and cannot even begin to imagine what the dealership would have charged me to diagnose and fix this problem.

Oh, total cost of the repair - $1 worth of wire, not including the 2 hours it took to fix it, and a very expensive dinner I plan to buy for my helper!

 

Nice! Potential tech article, perhaps?

 

the pin out information of the harness going to the ABS controller itself.

Again, I also have the login information needed to recode the soft code to the ABS controller and the procedure to reset the steering angle sensor.

I'm really thinking that when people have troubles with the ABS/ESP/brake light issue, the dealership just jumps to, "You need a new ABS controller" - at $1000, it seems a bit high for a "guess". I have to think that the ABS controller can't be going bad with the frequency some people are getting these replaced. It's just a computer and we don't see people having their stock ECUs replaced over and over again!

 

I heard all about from WindycityS4, sounded like a bia(*^(&ch to fix.

 

Please, you have to post pics of the original "Ghetto" wiring...

 

pillar. I had an intermitant tail brake light failure and after checking fuses, bulbs and connections at the front and back of the car I took it in to Audi service. The tech found the connector in the driverside B-pillar wasslightly seperated causing the the intermitant failure.

This may or may not apply to your situation but I thought I'd offer it out there for the braintrust to consider.

 

would ever be right again. Mainly, when lining up the wire cutters next to factory wiring harness and squeezing to cut the wire - not for the faint of heart. WindyCityS4 had located the wire and actually called me over to make the actual cut - he wanted no responsibility regarding the possible damage. It was pretty funny.

It was actually quite humorous - we kept saying, the blue one right? The blue one with green stripes right? It's the blue one right? Yeah, the blue one, right?

We decided we would not make very good bomb squad candidates!

 

imagine the actual wire was cut somewhere.

Who knows, at least it's fixed!

 

between the new wire and the the harness connecting to the ABS pump went. It looked a bit nicer when we were done:

<img src="http://pictureposter.audiworld.com/36810/wiring-1.jpg">

Then the connection to the wiring harness going to the ABS controller itself:

<img src="http://pictureposter.audiworld.com/36810/wiring-2.jpg">

And, finially, the routing of the wire. It really was not so bad until you got going over 75mph - at that point, the wire kept smacking into the side of the car, making a funny noise....that's when we decided to route it through the ECU box, down through the firewall, under the driver's side knee bolster and back under the trim to the back seat. I think it came out nicer that way!

<img src="http://pictureposter.audiworld.com/36810/wiring-3.jpg">

 

hi im sorry its a while you posted this but im having an intermitent brake light failure with abs and esp light on. you said b pillar connector was loose where was it by? the connector that go to the rear door? please i will greatly appreciate it if you could help me out.