IN04F-02
- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN-17
17 Author: Date:
1997 SUPRA (RM502U)
HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS
GENERAL INFORMATION
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, troubleshoot-
ing of these systems is not complex. If you have adequate understanding of the system and a basic knowl-
edge 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 ac-
curate and effective troubleshooting, and is compiled for the following major ECU controlled systems:
SystemPage
1. Engine (2JZ-GE)DI-1
2. Engine (2JZ-GTE)DI-145
3. Automatic Transmission (2JZ-GE)DI-316
4. Automatic Transmission (2JZ-GTE)DI-371
5. Anti-Lock Brake SystemDI-440
6. ABS & Traction control SystemDI-499
7. Supplemental Restraint SystemDI-555
8. Theft Deterrent SystemDI-608
9. Cruise Control SystemDI-660
11. Air Conditioning SystemDI-71 1
The troubleshooting procedure and how to make use of it are described on the above pages.
FOR USING OBDII SCAN TOOL OR TOYOTA HAND-HELD TESTER
Before using the OBDII scan tool or TOYOTA hand-held tester, the OBDII scan tool's instruction book
or TOYOTA hand-held tester's operator manual should be read thoroughly.
If the OBDII scan tool or TOYOTA hand-held tester cannot communicate with ECU controlled systems
when you have connected the cable of the OBDII scan tool or TOYOTA hand-held tester to DLC3,
turned the ignition switch ON and operated the scan tool, there is a problem on the vehicle side or tool
side.
(1) If communication is normal when the tool is connected to another vehicle, inspect the diagnosis
data link line (Busline) or ECU power circuit of the vehicle.
(2) If communication is still not possible when the tool is connected to another vehicle, the problem
is probably in the tool itself, so perform the Self Test procedures outlined in the Tester Operator's
Manual.
