45-18
 
     
Anti-lock Brake System (ABS), 
Bosch 5.3 
      A traction control system (TCS/ASR) is available 
as optional equipment for front-wheel-drive 
models.  
      The brake system of the ABS is split diagonally. 
The brake servo assistance is provided 
pneumatically by a vacuum brake servo unit.  
    
Hydraulic unit -a- and ABS control module -b- form a single unit. The 
combination of these two components is termed the hydraulic control 
unit.  
Sources of malfunctions are reduced as a result of the direct link between 
the two components.  
CAUTION! 
It is not possible to repair the hydraulic control unit. If faulty, it 
should be replaced. The bolts which connect the individual components of the 
hydraulic control unit must not be loosened. 
Pa
ge 1 of 6 Anti-lock Brake S
ystem 
(ABS
), Bosch 5.3
11/19/2002 htt
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pair&id=AUDI.B5.SU03.45.3