TROUBLE DIAGNOSES — How to Perform Trouble Diagnoses for Quick and Accurate Repair — Introduction

The A.B.S. system has an electronic control unit to control major functions. The control unit accepts input signals from sensors and instantly drives actuators. It is essential that both kinds of signals are proper and stable. At the same time, it is important that there are no conventional problems such as air leaks in the booster or lines, lack of brake fluid, or other problems with brake system. It is much more difficult to diagnose a problem that occurs intermittently rather than continuously. Most intermittent problems are caused by poor electric connections or faulty wiring. In this case, careful checking of suspicious circuits may help prevent the replacement of good parts. A visual check only may not find the cause of the problems, so a road test should be carried out. Before undertaking actual checks, take just a few minutes to talk to a customer who approaches with an A.B.S. 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 A.B.S. controlled vehicle. Using CONSULT, a full diagnostic test procedure can be carried out in a short time. NISSAN strongly recommend that CONSULT be used for A.B.S. Trouble Diagnosis. If, however, for some reason, CONSULT is not available, a basic pinpoint diagnostic procedure is included for continuity checking, etc.