Steady out a rough, hunting, or stalling idle with the Standard Ignition Idle Air Control Valve AC555, a direct-fit replacement for the listed applications: 1998-2005 Lexus GS300, 1998-2000 Lexus GS400, 2001-2005 Lexus GS430, 2001-2003 Lexus IS300, 1998-2000 Lexus LS400, 1998-2000 Lexus SC300, and 1998-2000 Lexus SC400.
The idle air control valve meters the volume of air that bypasses the closed throttle plate, letting the engine control module hold the commanded idle speed under changing loads like the A/C compressor and cold start.
Diagnose the cause of an idle concern before replacing, as these symptoms can have other sources.
Interchange: 50669 · AC4194 · 2-16840 · 216840 · 8967230020
Manufacturer part number AC555
This part cross-references / interchanges with the following part numbers:
What does this idle air control valve do?
It meters the air that bypasses the closed throttle plate, letting the engine control module hold a steady idle speed under changing loads such as cold start or A/C operation.
Will the AC555 fit my vehicle?
It is a direct-fit replacement for the 1998-2005 Lexus GS300, 1998-2000 GS400, 2001-2005 GS430, 2001-2003 IS300, 1998-2000 LS400, 1998-2000 SC300, and 1998-2000 SC400. Check the Buyer's Guide tab.
What are the signs of a failing IAC valve?
Common signs are a rough or fluctuating idle, unexpected stalling, hard starting, or an idle that hangs high. Diagnose the cause first, since these symptoms can have other sources.
What numbers does this part interchange with?
It cross-references 50669, AC4194, 2-16840 (216840), and 8967230020. The manufacturer part number is AC555.
Will replacing this valve fix my rough idle?
If a failed idle air control valve is the cause, this replaces it. A rough idle can also stem from other issues, so confirm the diagnosis before installing.
WARNING: These products can expose you to chemicals including lead and phthalates, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.
