IAC Valve Operation
WARNING: This page is about a different car, the 1995 Lexus SC 300. However, it is still accessible from the selected car via links, so may be relevant.
Remove IAC valve. See COMPONENT LOCATIONS under INTRODUCTION. Connect battery positive lead to terminals B1 and B2 of IAC valve. See Fig 1. To close IAC valve pintle, repeatedly ground terminals S1, S2, S3 and S4 in sequence. To open IAC valve pintle, repeatedly ground terminals S4, S3, S2 and S1 in sequence. Replace IAC valve if pintle does not open and close as specified.