General Information
WARNING: This page is about a different car, the 2004 Toyota 4Runner. 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 4RUNNER. 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:
GENERAL INFORMATION REFERENCE
FOR USING OBD II 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 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.
- If communication is normal when the tester is connected to another vehicle, inspect the diagnosis data link line (Bus oplus line) or ECU power circuit of the vehicle.
- 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 procedures outlined in the Tester Operator's Manual.