ABS 2 LED Tester Diagnostic Chart

Testing with the Bosch ABS 2 LED-Tester

Tester In Position 1 - 4:

Note: Vehicle wheels must be off the ground to perform steps 5 and 6. Carry out all testing consecutively for each wheel.

Tester In Position 5:

Tester In Position 6:

Final check:
^ assemble system
^ start engine; anti-lock indicator light in vehicle must go out
^ while the engine is running, actuate switch for anti-lock; indicator light in vehicle must come on
^ switch off engine and start it again; anti-lock indicator light must go out
^ drive vehicle at a speed above 20 mph (30 kph); anti-lock indicator must not come on
^ if the center and/or rear differential lock is engaged, the ABS indicator light must come on (5000 Quattro only)

If the ABS system does not function properly at the conclusion of the test procedure, replace the control unit and test drive the vehicle.