IAC System Circuit
WARNING: This page is about a different car, the 1995 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.
Perform IAC valve resistance and operation tests. If IAC valve resistance and operation are okay, check for open or shorted circuit between EFI main relay and IAC valve, and between IAC valve and ECM. See COMPONENT LOCATIONS under INTRODUCTION. If circuits are okay, IAC system circuit is okay.