Field Coil Test
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Lexus GS 430, 2004 Lexus GS 300, 2003 Lexus GS 430, 2003 Lexus GS 300, and 2002 Lexus GS 430. However, it is still accessible from the selected car via links, so may be relevant.
Using ohmmeter, check for continuity between starter solenoid lead and field coil brush lead. If continuity does not exist, replace field frame. Using ohmmeter, check for continuity between field coil end and field frame. If continuity exists, repair or replace field frame.