TROUBLE DIAGNOSES

The ABS system has an electronic control unit to control major braking functions. The control unit accepts input signals from sensors and utilises the data to instantly drive the actuators. It is essential that both input and output signals are correct and stable. It is also important to check for conventional problems: such as air leaks in booster lines, lack of brake fluid, or other problems with the brake system.

It is much more difficult to diagnose a problem that occurs intermittently rather than catastrophically. Most intermittent problems are caused by poor electric connections or faulty wiring. In this case, careful checking of suspicious circuits may help prevent the unnecessary replacement of good parts.

A visual check may not be sufficient to find the cause of the problems, so a road test should also be performed.

Before undertaking actual checks, take just a few minutes to talk with a customer who approaches with a ABS complaint. The customer is a very good source of information on such problems; especially intermittent ones. Through the talks with the customer, find out what symptoms are present and under what conditions they occur.

Start your diagnosis by looking for "conventional" problems first. This is one of the best ways to troubleshoot brake problems on an ABS controlled vehicle.