GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC K Sierra - 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. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.

    2. Object Number: 312513 Size: SH
  2. Disconnect the idle air control (IAC) valve harness connector.

    3. Object Number: 12909 Size: SH
  3. Remove the IAC mounting bolts.

    4. Object Number: 12910 Size: SH

    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.

  4. Remove the IAC valve and O-ring from the throttle body assembly.

Cleaning and Inspection Procedure
  1. Clean the IAC valve O-ring sealing surface, pantie 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 solvent 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, then remove the throttle body for a complete cleaning. Refer to Throttle Body Assembly Replacement .
  2. Inspect the IAC valve O-ring for cuts, cracks, or distortion. Replace if damaged.

Installation Procedure

    Object Number: 17065 Size: SH

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

  1. Replace the IAC valve O-ring if it is distorted, cracked, or cut.
  2. Measure the distance between the IAC valve pintle and mounting flange. Use finger pressure to slowly retract the pintle if the distance is more than 28 mm.

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

    6. 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.

  6. Install the IAC valve mounting bolts.

    7. Tighten
    Tighten the bolts to 3.1 N·m (26 lb in).


    Object Number: 312513 Size: SH
  7. Connect the IAC valve harness connector.
  8. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  9. 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.