GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1998 🢒 S10 Pickup - 4WD 🢒 Engine 🢒 Engine Controls - 4.3L 🢒 Idle Air Control Valve Replacement

Removal Procedure

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the negative battery cable.

    2. Object Number: 10940 Size: SH
  2. Disconnect the IAT sensor connector.

    3. Object Number: 309177 Size: SH
  3. Disconnect the breather tube from the air cleaner outlet duct.

    4. Object Number: 312278 Size: SH
  4. Remove the wing nut retaining the air cleaner outlet duct.

    5. Object Number: 424556 Size: SH
  5. Loosen the clamp on the outlet of the MAF sensor.
  6. Lift the air cleaner outlet duct from the throttle body and remove the assembly from the MAF sensor.

    7. Object Number: 312513 Size: SH
  7. Disconnect the IAC valve electrical connector.

    8. Object Number: 12909 Size: SH
  8. Remove the IAC valve mounting screws.

    9. Object Number: 12910 Size: SH
  9. Remove the IAC valve and O-ring from the throttle body assembly.

Cleaning and Inspection Procedure

    Notice: If the IAC valve has been in service: DO NOT push or pull on the IAC valve pintle. The force required to move the pintle may damage the threads on the worm drive. Also, DO NOT soak the IAC valve in any liquid cleaner or solvent, as damage may result.

  1. Clean the IAC valve O-ring sealing surface, pintle valve seat, and air passage.
    2. • Remove excess carbon deposits with a small amount of carburetor cleaner on a parts cleaning brush. Follow any instructions on the cleaner container regarding cleaner usage.
    • Do not use a cleaner containing an extremely powerful solvent such as methyl ethyl ketone.
    • Shiny spots on the pintle and seat do not represent a bent or misaligned pintle shaft.
    • If heavy deposits are present in the air passage, remove the throttle body for a complete cleaning. Refer to Throttle Body Assembly Replacement .

    Important:  Do not reuse the original O-ring.

  2. Replace the IAC valve O-ring.

Installation Procedure

    Object Number: 17065 Size: SH

    Notice: The IAC valve may be damaged if installed with the cone (pintle) extended more than 28 mm (1-1/8 in). Measure the distance that the valve is extended before installing a new valve. The distance from the idle air control valve motor housing to the end of the idle air control valve pintle should be less than 28 mm (1-1/8 in). Manually compress the pintle until the extension is less than 28 mm (1-1/8 in).

    Important: Use an identical part when installing a new Idle Air Control (IAC) valve. The IAC valve pintle shape and dimensions are designed for specific applications.

  1. On a new IAC valve, measure the distance between the IAC valve pintle and mounting flange. Use finger pressure to slowly retract the pintle if the distance is greater than 28 mm (1-1/8 in).

    2. Object Number: 12910 Size: SH
  2. Lubricate the IAC valve O-ring with clean engine oil.
  3. Align the flange holes with the mounting holes on the throttle body assembly.
  4. Insert the IAC valve through the O-ring into the throttle body assembly.

    5. Object Number: 12909 Size: SH

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

    Important: The screws used to attach the IAC valve are coated with thread locking adhesive. Clean the attaching screw threads and apply thread locking material GM P/N 1052624 or equivalent.

  5. Install the IAC valve mounting screws.

    6. Tighten
    Tighten the screws to 3 N·m (27 lb in).


    Object Number: 312513 Size: SH
  6. Connect the IAC valve electrical connector.

    7. Object Number: 424556 Size: SH
  7. Install the air cleaner outlet duct.

    8. Object Number: 312278 Size: SH
  8. Tighten the air cleaner outlet duct wing nut.
  9. Secure the air cleaner outlet duct to the MAF sensor.

    10. Tighten
    Tighten the air cleaner outlet duct clamp to 4 N·m (35 lb in).


    Object Number: 309177 Size: SH
  10. Connect the breather tube to the air cleaner outlet duct.

    11. Object Number: 10940 Size: SH
  11. Connect the IAT sensor connector.
  12. Connect the negative battery cable.
  13. Perform the following steps to reset the IAC valve pintle position:

IAC Valve Reset Procedure
  1. Turn ON the ignition for 20 seconds.
  2. Turn OFF the ignition for 10 seconds.
  3. Start the engine.
  4. Check for the proper idle speed.