Safety Precautions

If special testing equipment is required during road test, note the information:
^ Test equipment must always be secured to the rear seat and operated from there by a second person.
^ If test and measuring equipment is operated from the passenger seat, the person seated there could be injured in the event of an accident involving deployment of the passenger-side airbag.
^ Connect VAG1551 scan tool and select the control module for brake electronics with ignition switched on (address word 03).





Indicated on display:
^ Press buttons -0- and -8-. This selects "Read Measuring Value Block" function 08.





Indicated on display:
^ Press -Q- button to confirm input.





Indicated on display:
^ Enter display group number, Refer to Overview of selectable display group numbers.








Overview of selectable display group numbers

Test sequence and test tables with measured values
Checking wheel speed sensors
Display group number 001
^ Press buttons -0-, -0- and -1-.
^ Press -Q- button to confirm input.





Measuring value block always has 4 display fields (arrows). Values 1 to 4 in the individual display fields can be interpreted according to the test table.





Indicated on display: (with vehicle at standstill)
If the -> button is pressed, the work sequence "Read measuring value block" must be reinitiated using buttons -0- and -8-.

Note: Note the information for display group number 001:

The current wheel speeds are indicated. This is useful for checking wheel speed sensor allocation by wheel. (Vehicle must be raised and a second technician must turn wheel by hand)





1) On Board Diagnostic (OBD) will be terminated by the ABS Control Module (W/EDL) -J104- if road speed exceeds 19 km/h.

Checking brake light switch, voltage at motor for return pump and relay for solenoid valve
Display group number 002
^ Press buttons -0-, -0- and -2-.
^ Press -Q- button to confirm input.





^ Measuring value block always has 4 display fields (arrows). Values 1 to 4 in the individual display fields can be interpreted according to the test table.





Indicated on display: (with vehicle at standstill)
If the -> button is pressed, the work sequence "Read measuring value block" must be reinitiated using buttons -0- and -8-.











Voltage for solenoid valve
^ 0-> no voltage present (malfunctioning)
^ 1-> voltage present (OK)

Perform electrical test

If there is voltage at the motor for return flow pump, replace the hydraulic control module.