Unusual ABS Fault - MOT Next friday so need quick fix.

[mr_fusion 0]

Ok, weird one this.

 

Here is the problem.

 

Start up car, ABS light comes on and stays on. Plug in the VAG COM, try to connect to the ABS, cannot be found.

 

Turn ignition off then on again, ABS light comes on then goes off like it should, connect VAG COM, finds ABS, no faults reported!

 

This problem is totally conisistent. Only thing I might add is that there is a push button ignition start as the switch broke and would not work on the ignition position (so the push start button is pressed to fire the car up)

 

I have a new switch so I can fit it at the weekend, but I don't fully understand how this would effect the ABS.

 

I know everyone is just thinking "connect the new switch and see what happens" but I am pre-empting that this will not fix the problem and looking for other possible solutions as well.

 

Any thoughts or anyone had a similar issue?

[G60Jet 1]

mine used to do something similar, Go jet wash the wheels and brakes, always fixed mine. but i never had vag com

[mr_fusion 0]

I may have found a very useful bit of info on google!

 

http://www.mightyautoparts.com/pdf/arti ... 20light%22

 

 

"VOLKSWAGEN WITH CONTINUOUS ABS LIGHT

Volkswagen has identified that a problem with the

ignition switch may result in the ABS warning lamp

being illuminated on Passat, Corrado and EuroVan models

from 1993. VW Bulletin No. 93.01 identifies that an

ABS warning light which does not go out after vehicle

start-up may be caused by the ignition switch/lock not

fully returning from the “start” position (terminal 50) to

the “run” position (terminal 15). If the switch/lock does

not return to the run position, circuits controlled or

powered by terminal X (for example headlights, evaporator

fan and ABS hydraulic pump) will not function. A

non-functioning ABS hydraulic pump will cause the ABS

warning lamp to stay on. If the ignition switch binds or

does not return smoothly from the start to run position,

check for misadjustment of the shift/lock cable, an

ignition switch sticking or binding, or a burr on an

improperly cut and deburred ignition key."

[dr_mat 0]

That sounds like the bunny.

You other possibility is the ABS power relay being a little sticky - it needs a second shove to get it going?

[mr_fusion 0]

Yeah, that was going to be my next option.

 

From experience getting at the relays is a a whole lot easier than getting at the small screw that hold the ignition switch on..

 

Oh well, lots to do this weekend:

 

Fix the ABS problem

Oil Change

Oil Filter Change

Fit Mocal Oil Cooler Kit (if it actually arrives today!)

Bit of sanding, filling, painting of O/S rear wing (if weather permits)

Same for both bumpers.

[kongo127 0]

mr_fusion, Nice Find!

[Guest]

I have a similar inconsistant error on mine.

 

I had a dodgey connection on my headunit, and the battery kept running flat, and after a few times of jump starting the ABS light came on.

 

I fixed the live feed problem, and now the ABS stays on every couple of days, but is fine when I come back to it.

 

I was thinking the power problem buggered up the ABS Brain?

[mr_fusion 0]

Good News.

 

Swapped the ignition switch, ABS now works perfectly.

 

Definately something to think about if anyone else has an ABS light problem.