How To Proceed With Troubleshooting
WARNING: This page is about a different car, the 2005 Lexus GS 430 and 2005 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.
HINT:
This ECU is connected to the multiplex communication system. Therefore, be sure to check that there is no troubles in the multiplex communication system before performing the troubleshooting. (See MULTIPLEX COMMUNICATION SYSTEM - DIAGNOSTICS ).