General Information

INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: GENERAL INFORMATION

GENERAL INFORMATION
- A large number of ECU controlled systems are used in the LEXUS ES350. 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.
- FOR USING Techstream
HINT: *: Techstream is the name for the diagnostic tester in North America.

- Before using Techstream, read the operator's manual thoroughly.
- If the Techstream cannot communicate with the ECU controlled systems when the Techstream is connected to the DLC3 with the engine switch on (IG) and Techstream turned on, there is a problem on the vehicle side or Techstream side.
1. If communication is normal when Techstream 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 not possible when Techstream is connected to another vehicle, the problem is probably in Techstream itself. Perform the Self Test procedures outlined in the Techstream operator's manual.