Failed MOT today

**HAWKS** · 15-06-2016,09:53 PM

The old girl failed an MOT today.
ABS warning light on the display. I get 2 chimes when i start her up then the brake sign on the display.
The guy couldn't read the fault on his system, so got his mate to read it.
Low voltage, ABS. Cant reset fault. No code given.
I think she's sulking now I've replaced her.
What could be the fault?

**zollaf** · 15-06-2016,09:58 PM

low voltage abs, clue could be there

check the strip fuses above the battery if you have them, or the big main abs fuse.

**HAWKS** · 15-06-2016,11:12 PM

Cheers Zollaf.
I will check the fuses you have mentioned.
I was thinking abs wheel sensor,then which one?

**zollaf** · 16-06-2016,08:17 AM

a sensor fault will generally come up as a code. if the fuse is ok i would get a vcds scan ..

**HAWKS** · 11-07-2016,08:36 PM

I ve checked and cleaned the fuses.
Ive checked the rear abs sensor connections under back seats, still comes on.
I have tried to get it scanned by another garage, but it wouldn't connect to the car.
The last 2 garages both had Snap On units that tried to scan the car. Both said that it wouldn't connect.
Will the Snap On Machines not read 2000 A4 B5 cars???
Ive PM people nearest to me on the VCDS map, no response.
Mods, how upto date is this map??
Can anyone help with this.
Cheers.
Graham.

**spartacus 68** · 13-07-2016,10:46 PM

Out of interest what's the voltage on the battery? Should be around 12.4v on healthy one. I changed the battery on my old 2001 Amtrak shortly before selling it, and although it didn't have ABS faults it did have all the hallmarks of causing problems. It would have been original Audi kit.

**HAWKS** · 13-07-2016,11:44 PM

The battery is good.
Trying to find someone near me with vcds is proving difficult.
Most garages seem to have Snap On scanners that won't connect to the car.
I might just pick a corner and strip down the hubs to clean each wheel sensor and abs rings.

**Eshrules** · 14-07-2016,07:48 AM

Originally Posted by HAWKS

The battery is good..

Have you had it checked? A battery can turn a car over but sometimes still need replacing.

Winter's usually the time when people find that one out

**HAWKS** · 14-07-2016,08:19 AM

Let's put it this way.
Ive bought a TT so she's not been used since I drove the A4 to my mums driveway.
3weeks later, I went to my mums when someone was coming to try an scan it. She spun over as fast as normal without heaters an burst into life.
Before I bought the TT, she was my faultless daily drive with the only fault being the abs lights.
So I can rule out the battery.
thanks for your replies.
Will Snap On units scan A4. If they will,then I might have a bigger problem.
2 have tried to scan it.

**Eshrules** · 14-07-2016,09:12 AM

Originally Posted by HAWKS

Let's put it this way.
Ive bought a TT so she's not been used since I drove the A4 to my mums driveway.
3weeks later, I went to my mums when someone was coming to try an scan it. She spun over as fast as normal without heaters an burst into life.
Before I bought the TT, she was my faultless daily drive with the only fault being the abs lights.
So I can rule out the battery.
thanks for your replies.
Will Snap On units scan A4. If they will,then I might have a bigger problem.
2 have tried to scan it.

Sorry, maybe I wasn't clear with my question - has your battery been tested?

A battery can start a car and still be under voltage, leaving a car for 3 weeks without using it and then struggling to obtain a scan would suggest there may be something amiss with the battery.

Most places will do a battery health check for free so it would be worth doing to rule that out as a possible cause, Kwik Fit would fit you in at a moments notice and it'll take 10 minutes at the most.

At least that's what I'd do, start with the free & cheap stuff first - easiest and simplest way to rule out potential problem causers.