Diagnosis & Repair
WARNING: This page is about a different car, the 2002 Lexus GS 430. However, it is still accessible from the selected car via links, so may be relevant.
Retrieve trouble codes. See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. If other codes are displayed, diagnose and repair those codes first and retest. If only DTC P1129 is displayed, replace ECM. Clear and retrieve trouble codes. If DTC P1129 is displayed again, replace throttle body and retest.