Standard Ignition AC539 Idle Air Control Valve

Brand Standard Ignition AC539
Terminal Type Blade
Fits Honda · 12 vehicles

Idle air control valve. Regulates airflow to help maintain a steady idle.

Female connector. Features a 3-blade terminal layout for straightforward hookup.

Cross-references Karlyn 50653, Standard Ignition AC539 and 2-16824 for the same application. See all 5.

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Idle Air Control Valve for Honda S2000

Standard Ignition AC539 is an idle air control valve for 2000-2005 Honda S2000 applications. It is built with a female connector, two hose connections, and a 3-blade male terminal layout for direct replacement service on the specified vehicle range.

Key Features

  • Idle air control valve for fuel injection system service
  • Female connector with 3 male blade terminals
  • Two hose connector ports for the listed application
  • Direct-fit replacement for 2000-2005 Honda S2000
  • Standard Ignition AC539 part number for catalog matching

Detailed Description

Standard Ignition AC539 is an idle air control valve used in the air and fuel delivery system to regulate bypass air at idle on the Honda S2000. For 2000-2005 Honda S2000 models, this component supports stable idle control when the original valve is worn, sticking, or no longer responding correctly to engine demand. The AC539 part number is also useful when cross-checking replacement listings for the same application.

This part cross-references Karlyn 50653 for the same application.

What It Helps Solve

  • Unstable or fluctuating idle speed
  • Stalling when the engine returns to idle
  • Idle speed that stays too high after throttle release
  • Rough idle behavior on 2000-2005 Honda S2000 models
  • Idle control faults related to a worn valve assembly

Installation Notes and Tips

Verify connector style, terminal count, and hose connection layout before installation. Clean the mating surfaces and inspect nearby intake and vacuum passages for buildup or leaks that can affect idle quality. Confirm the replacement matches the original AC539 configuration for your Honda S2000 before final assembly.

Quality Assurance

Standard Ignition supplies replacement ignition and engine management components for service applications, and AC539 is cataloged for the listed Honda S2000 fitment. Confirm vehicle year and application details against the fitment data before ordering.

This part fits 12 vehicles
Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
YearMakeModelLitersCylindersPositionNotes
2005HondaS2000N/APrimary application for specific vehicle models ~ Idle Air Control Valve
2005HondaS20002.2LL4N/ACompatible with various car models.
2004HondaS2000N/APrimary application for specific vehicle models ~ Idle Air Control Valve
2004HondaS20002.2LL4N/ACompatible with various car models.
2003HondaS2000N/APrimary application for specific vehicle models ~ Idle Air Control Valve
2003HondaS20002.0LL4N/ACompatible with various car models.
2002HondaS2000N/APrimary application for specific vehicle models ~ Idle Air Control Valve
2002HondaS20002.0LL4N/ACompatible with various car models.
2001HondaS2000N/APrimary application for specific vehicle models ~ Idle Air Control Valve
2001HondaS20002.0LL4N/ACompatible with various car models.
2000HondaS2000N/APrimary application for specific vehicle models ~ Idle Air Control Valve
2000HondaS20002.0LL4N/ACompatible with various car models.
Directly replaces or cross-references 5 part numbers
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.
Karlyn — 50653Standard Ignition — AC5392-1682436460PCX003AC4172