General Information
WARNING: This page is about a different car, the 2004 Lexus IS 300. However, it is still accessible from the selected car via links, so may be relevant.
A large number of ECU controlled systems are used in the LEXUS IS300. In general, ECU controlled systems are considered to be a very intricate, requiring a high level of technical knowledge to troubleshoot. However, following the problem checking procedures of the ECU controlled system's circuits carefully is not complex. If you have an adequate understanding of the system and a basic knowledge of electricity, accurate diagnosis and necessary repair can be performed.
This manual emphasizes the above standpoint to help service technicians perform accurate and effective troubleshooting. Detailed information on major ECU controlled systems in this vehicle are outlined below:
IDENTIFYING SYSTEM AND PAGE DESCRIPTION CHART
| System | See |
|---|---|
| 1. Engine | HOW TO PROCEED WITH TROUBLESHOOTING |
| 2. Automatic Transmission | HOW TO PROCEED WITH TROUBLESHOOTING |
| 3. ABS with EBD & BA & TRAC System | DIAGNOSTIC TESTS |
| 4. ABS with EBD & BA & TRAC & VSC System | DIAGNOSTIC TESTS |
| 5. Supplemental Restraint System | DIAGNOSTICS |
| 6. Theft Deterrent System | HOW TO PROCEED WITH TROUBLESHOOTING |
| 7. Cruise Control System | HOW TO PROCEED WITH TROUBLESHOOTING |
| 8. Engine Immobilizer System | HOW TO PROCEED WITH TROUBLESHOOTING |
| 9. Combination Meter System | HOW TO PROCEED WITH TROUBLESHOOTING |
| 10.Body Control System | HOW TO PROCEED WITH TROUBLESHOOTING |
| 11.Multiplex Communication System | HOW TO PROCEED WITH TROUBLESHOOTING |
| 12.LEXUS Navigation System | HOW TO PROCEED WITH TROUBLESHOOTING |
| 13.Air Conditioning System | HOW TO PROCEED WITH TROUBLESHOOTING |
FOR USING OBDII SCAN TOOL OR 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.
- 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.
- 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.