technical data TOYOTA AVALON 2001 Service Repair Manual

IN05Y-17
- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN-19
19 Author
: Date
:
2001 AVALON (RM808U)
HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS
GENERAL INFORMATION
A large number of ECU controlled systems are used in the AVALON. 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.
SystemPage
1. EngineDI-1
2. Automatic TransaxleDI-158
3. Anti-Lock Brake System With Electronic Brake Force Distribution (EBD)DI-210
4. ABS With EBD & BA & TRAC & VSC SystemDI-250
5. Supplemental Restraint SystemDI-347
6. Power Seat Control System (w/ Driving position memory)DI-488
7. Theft Deterrent SystemDI-517
8. Cruise Control SystemDI-549
9. Engine Immobilizer SystemDI-597
10.Body Control SystemDI-615
11. Driver Door Control SystemDI-676
12.Passenger Door Control SystemDI-700
13.Multiplex Communication SystemDI-718
14.Air Conditioning SystemDI-752
FOR USING OBD II SCAN TOOL OR TOYOTA HAND-HELD TESTER

Before using the scan tool or tester, the scan tool's instruction book or tester's operator manual should
be read thoroughly.

If the scan tool or tester cannot communicate with ECU controlled systems when you have connected
the cable of the scan tool or 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 (Bus
line) 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 outline in the Tester Operator's
Manual.