General Information

A large number of ECU controlled systems are used in the LEXUS SC430. In general, ECU controlled systems are considered to be very intricate, requiring a high level of technical knowledge to troubleshoot. However, most problem checking procedures only involve inspecting the ECU controlled system's circuits one by one. An adequate understanding of the system and a basic knowledge of electricity is enough to perform effective troubleshooting, accurate diagnoses and necessary repairs. Detailed information and troubleshooting procedures on major ECU controlled systems in this vehicle are outlined below:

FOR USING SCAN TOOL OR HAND-HELD TESTER 

• Before using the tester or scan tool, the scan tool's instruction book or tester's operator manual should be read thoroughly.
• If tester or scan tool cannot communicate With the ECU controlled systems when you have connected the cable of the 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 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 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 procedure outlined in the Tester Operator's Manual