Many Audi and VW models manufactured starting in the later '90S and continuing to present, use the Bosch 5.3 ABS controller, which is prone to catastrophic failure, ostensibly due to defective design. This module controls multiple brake-related functions including the ABS which is important for winter driving, but the most critical function of this module is probably the electronic brake force distribution, or ebd. These vehicles are designed such that if the ebd is inoperative, the proportion of hydraulic force applied to the rear brakes during emergency braking is as great as it is during moderate braking effort when there is minimal transfer of vehicle weight to the front wheels. The ebd is supposed to adjust the front/rear braking distribution dynamically according to the measure of the deceleration, so that the rear wheels will not lock up during emergency braking. If this module should fail during emergency braking on dry pavement, the rear wheels could lock up and cause an accident which could easily include fatalities. This is an expensive repair for owners, costing roughly $2000, and many owners have probably put off the repair indefinitely. Evidence which can be found through a simple web search, suggests that the problem is widespread, and that if it has not already led to serious accidents, it is only a question of time. This problem is genuine, and VW/Audi should be compelled to take immediate corrective action.

- Littleton, CO, USA