Lexus ES300 (2002 year). Service manual - part 276
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INTRODUCTION
HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
20
2002 LEXUS ES300 REPAIR MANUAL (RM911U)
HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS
GENERAL INFORMATION
A large number of ECU controlled systems are used in LEXUS ES300. In general, the ECU controlled system
is considered to be a very intricate system requiring high level of technical knowledge and expert skill to trou-
bleshoot. The fact is, however, 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 basic knowledge of electric-
ity, 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 an 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.
System
Page
1. SFI System
2. Electronic Modulated Suspension System
3. ABS with EBD System
4. ABS with EBD & BA & TRAC & VSC System
5. Electronic Controlled Automatic Transmission [ECT]
6. Air Conditioning System
7. Supplemental Restraint System
8. Lighting System
9. Wiper and Washer System
10.Audio System
11.LEXUS Navigation System
12.Power Window Control System
13.Power Mirror Control System
14.Combination Meter
15.Front Power Seat Control System (with memory)
16.Power Door Lock Control System
17.Wireless Door Lock Control System
18.Luggage Comportment Door Opener System
19.Key Unlock Warning System
20.Engine Immobiliser System
21.Theft Deterrent System
22.Multiplex Communication System
23.Cruise Control System
FOR USING OBDII SCAN TOOL OR HAND-HELD TESTER
HINT:
Before using the scan tools 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 the ECU controlled systems when you have con-
nected the cable of the scan tool or tester to the DLC3 with the ignition switch and tester turned ON,
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 Tester Oper-
ator’s Manual.