Toyota Supra JZA80

How to troubleshoot ECU controlled systems

A large number of ECU controlled systems are used in the TOYOTA SUPRA. In general, the ECU controlled system is considered to be a very intricate system requiring a high level of technical knowledge and expert skill to troubleshoot. However, the fact is that if you proceed to inspect the circuits one by one, troubleshooting of these systems is not complex. If you have adequate understanding of the system and a basic knowledge of electricity, accurate diagnosis and necessary repair can be performed to locate and fix the problem. This manual is designed through emphasis of the above standpoint to help service technicians perform accurate and effective troubleshooting, and is compiled for the following major ECU controlled systems:

The troubleshooting procedure and how to make use of it are described on the following pages.

For using OBDII scan tool or Toyota hand-held tester

This guide is based on the book edition Toyota (RM502U, 1997)