ABS warning light - A4 (B6)

[Arthur Marks]

Woops. Turned out the plug to the sensor had disconected itself when I 
removed the coolant reservoir doing the other work. It's all good now. 
Thanks.

--Art

----- Original Message ----- 
From: Arthur Marks
To: Mark Rosenkrantz
Cc: a4 at audifans.com ; quattro at audifans.com
Sent: Tuesday, April 13, 2010 5:01 PM
Subject: Re: ABS warning light - A4 (B6)


Thanks for the replies so far.

I didn't bleed them yet (nor did I open them). Was still planning on doing
the rear pads and then flushing with new fluid. For now I sucked some fluid
out of the reservoir before retracting the front pistons.

Bentley for my '03 shows G201 as replaceable on the "hydraulic control unit"
(abs pump?).

Haven't had a chance to check on some of these things. Will need a second
person to check pressure with brakes applied as my computer with VAG-Com is
in the house with an extension to the vehicle.

--Art




----- Original Message ----- 
From: Mark Rosenkrantz
To: Arthur Marks
Cc: quattro at audifans.com ; a4 at audifans.com
Sent: Tuesday, April 13, 2010 1:59 PM
Subject: Re: ABS warning light - A4 (B6)


Art,

Did you open up the brake hydaulics and/or bleed them?  If not, retracting
the piston might've lodged some sediment in the ABS pump.  If you did, air
might be trapped in the ABS.

There are two brake pressure switches, one is the brake (foot pedal) switch
and if it's stuck on, so will your tail lamps be iluminated.  Also,
incorrect bulb in the rear can do that with the tail lights on (back feeding
to the brake circuit).  Grab someone to do a quick test there (brake lights
with and without headlamps).

G201 is internal in the ABS pump.  I don't know if the switch is available
or if the entire ABS pump would need replaced.  From recollection, you can
check it's readings in both the ABS and ECU measuring blocks to read the
value with the brakes applied and released.  You can also try doing a basic
setting to the ABS to recalibrate.  I'd bleed the entire system, including
ABS pump first.

A sticking component (holding back pressure) could cause this as well.  I've
seen brake lines acting as check valves, sticky master cylinders, etc.

Mark Rosenkrantz




On Tue, Apr 13, 2010 at 11:49 AM, Arthur Marks <aamarks at cox.net> wrote:

I did my brake pads and replaced a cv axle, and after the job the ABS and
ESP light is on and brake warning light is blinking. Tried to clear the one
error code and it comes back immediately:

  Vag-com (http://www.ross-tech.com)
    Control Module Part Number: 8E0 614 517 H
      Component and/or Version: ABS/ESP allrad      2328
                    Software Coding: 04277
                    Work Shop Code: WSC 06435
  1 Fault Found:
  01435 - Brake Pressure Sensor 1 (G201)
       57-00 - Electric Circuit Failure

The brakes work fine though I haven't done a hard stop to test the ABS. Any
ideas? The new pads seem to have the proper plug for the wear sensor, and
the new axle has the notches for the ABS.
I notice readings of 291.32 bar for brake pressure readings in the measuring
blocks which must be wrong.

Thanks,
--Art



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