General Information

A large number of ECU controlled systems are used in the LEXUS SC430. In general, the ECU controlled system is considered to be a very intricate system requiring high level of technical knowledge and expert skill to troubleshoot. The fact is, however, that if you proceed to inspect the circuit inspections one by one, troubleshooting of these systems is not complex. If you have adequate understanding of the system and basic knowledge of electricity, accurate diagnosis and necessary repair can be performed to locate and fix the problem. This information 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 procedures and how to make use of it are described on the following:

SYSTEM INDEX

System	Go To
1. SFI System	SYSTEM & COMPONENT TESTING
2. TIRE PRESSURE WARNING SYSTEM	TIRE PRESSURE WARNING SYSTEM - DIAGNOSIS
3. ABS WITH EBD & BA & TRAC & VSC SYSTEM	ABS WITH EBD & BA & TRAC & VSC SYSTEM - DIAGNOSIS
4. ELECTRONIC CONTROLLED AUTOMATIC TRANSMISSION [ECT]	ELECTRONIC CONTROLLED AUTOMATIC TRANSMISSION
5. POWER TILT AND POWER TELESCOPIC STEERING COLUMN	POWER TILT AND POWER TELESCOPING STEERING COLUMN
6. PROGRESSIVE POWER STEERING SYSTEM	PROGRESSIVE POWER STEERING SYSTEM - DIAGNOSIS
7. AIR CONDITIONING SYSTEM	AIR CONDITIONING SYSTEM - DIAGNOSIS
8. Supplemental Restraint System
9. LIGHTING SYSTEM	LIGHTING SYSTEM - DIAGNOSIS
10. WIPER AND WASHER SYSTEM	WIPER AND WASHER SYSTEM - DIAGNOSIS
11. AUDIO SYSTEM	AUDIO SYSTEM - DIAGNOSIS
12. LEXUS NAVIGATION SYSTEM	LEXUS NAVIGATION SYSTEM - DIAGNOSIS
13. LEXUS LINK SYSTEM	LEXUS LINK SYSTEM - DIAGNOSIS
14. POWER WINDOW CONTROL SYSTEM	POWER WINDOW CONTROL SYSTEM - DIAGNOSIS
15. POWER MIRROR CONTROL SYSTEM	POWER MIRROR CONTROL SYSTEM - DIAGNOSIS
16. DEFOGGER SYSTEM	DEFOGGER SYSTEM - DIAGNOSIS
17. COMBINATION METER	COMBINATION METER - DIAGNOSIS
18. FRONT POWER SEAT CONTROL SYSTEM (WITH MEMORY)	FRONT POWER SEAT CONTROL SYSTEM (W/MEMORY) - DIAGNOSIS
19. POWER DOOR LOCK CONTROL SYSTEM	POWER DOOR LOCK CONTROL SYSTEM - DIAGNOSIS
20. WIRELESS DOOR LOCK CONTROL SYSTEM	WIRELESS DOOR LOCK CONTROL SYSTEM - DIAGNOSIS
21. LUGGAGE COMPARTMENT DOOR OPENER SYSTEM	LUGGAGE COMPARTMENT DOOR OPENER SYSTEM - DIAGNOSIS
22. FUEL LID OPENER SYSTEM	FUEL LID OPENER SYSTEM - DIAGNOSIS
23. KEY REMINDER WARNING SYSTEM	KEY REMINDER WARNING SYSTEM - DIAGNOSIS
24. ENGINE IMMOBILIZER SYSTEM	ENGINE IMMOBILIZER SYSTEM - DIAGNOSIS
25. THEFT DETERRENT SYSTEM	THEFT DETERRENT SYSTEM - DIAGNOSIS
26. RETRACTABLE HARDTOP SYSTEM	RETRACTABLE HARDTOP SYSTEM - DIAGNOSIS
27. MULTIPLEX COMMUNICATION SYSTEM	MULTIPLEX COMMUNICATION SYSTEM - DIAGNOSIS
28. CRUISE CONTROL SYSTEM	CRUISE CONTROL SYSTEM - DIAGNOSIS

FOR USING SCAN TOOL OR HAND-HELD TESTER

Before using the tester, the tester's operator information should be read thoroughly.
If the tester cannot communicate with the ECU controlled systems when you have connected the cable of the 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 diagnosis 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 problem is probably in the tester itself, so perform the Self Test procedures outlined in the Tester Operator's information .