Toyota Corolla 2004 Repair Manual - HOW TO TROUBLESHOOT ECU CONTROLLEDSYSTEMS

–INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED

SYSTEMS

01–19

HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS

01034–08

GENERAL INFORMATION

There are many ECU controlled systems used in the COROLLA. In general, ECU controlled system are con­sidered to be very intricate and require a high level of technical knowledge and expert skill to troubleshoot.
The fact is, however, that if you proceed by inspecting the circuits one by one, troubleshooting of these sys­tems is not complex. If you have adequate understanding of the system and basic knowledge of electricity,
the problem can be accurately diagnosed and fixed. This manual is designed based on the above principle
to help service technicians perform accurate and effective troubleshooting, and is compiled for the following
major ECU controlled systems:
The troubleshooting procedures are described on the following pages.

System Page

1. SFI System 05–1

2. ABS with EBD System 05–294

3. Electronic Controlled Automatic Transaxle [ECT] 05–346

4. Supplemental Restraint System 05–421

5. Audio System 05–596

6. Combination Meter 05–638

7. Power Door Lock Control System 05–670

8. Wireless Door Lock Control System 05–685

9. TOYOTA Vehicle Intrusion Protection System 05–700

10.Cruise Control System 05–742

FOR USING HAND–HELD TESTER

 Before using the tester, the tester’s operator manual should be read thoroughly.
 If the tester cannot communicate with the ECU controlled systems when you have connected the cable

of tester to the DLC3, turned the ignition switch ON and operated the tester, there is a problem on the
vehicle side or tester side.
(1) If the communication is normal when the tester is connected to another vehicle, inspect the diag-

nosis data link line (Busline) or ECU power circuit of the vehicle.

(2) If the communication is still impossible when the tester is connected to another vehicle, the prob-

lem is probably in the tester itself, so perform the Self Test procedures outlined in the T ester Oper­ator ’s Manual.

2004 COROLLA (RM1037U)

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