Design of a Fault Diagnostic System for an ABS Based on Dual-CPU Structure

A fault diagnostic system with dual-CPU is designed and applied to the pneumatic anti-lock braking system (ABS) developed independently. ABS faults are classified according to the locations of possible faults through analysis of the basic configurations and operation principles of ABS. Diagnostic solutions for possible faults are raised and the corresponding diagnostic circuits and codes are designed. Fault diagnosis IS09141 protocol is adopted and corresponding communication circuits and interfaces are designed to transmit fault codes of ABS. An simple off-board tester is used to communicate with electrical control unit (ECU) and it attains to show, read, clear fault codes and look up information of the codes. It performs well according to road tests in various conditions.