This procedure covers the removal and replacement of the Idle Air Control (IAC) valve on the 3.5L EcoBoost V6 engine to restore proper idle control and engine performance.

Warnings

Tools required

Parts

• Idle Air Control Valve × 1 — Use OEM specification
• IAC valve gasket or O-ring (if equipped) × 1 — Typically included with valve

Preparation

1. Park vehicle on level ground and engage parking brake
2. Turn off engine and allow to cool for at least 30 minutes
3. Open hood and secure with prop rod
4. Disconnect negative battery terminal to prevent electrical faults
5. Remove engine cover by pulling upward on retention clips (no tools required)

Procedure

1. 1

   Locate the IAC valve or throttle body assembly
   On the 3.5L EcoBoost, the idle air control function is typically integrated into the electronic throttle body. Locate the throttle body on the driver's side of the engine, positioned between the intake tubes and the intake manifold. Use a work light to clearly identify the component and electrical connections.
2. 2

   Disconnect electrical connector
   Press the release tab on the throttle body electrical connector and carefully pull straight back to disconnect. If the connector is stubborn, gently wiggle while pulling. Do not pull on the wires themselves. Inspect connector pins for corrosion or damage.
3. 3

   Remove intake air duct
   Loosen the hose clamp securing the intake air duct to the throttle body using a flathead screwdriver or 7mm socket. Pull the duct away from the throttle body to provide access. You may need to disconnect a crankcase breather hose if present.
4. 4

   Remove throttle body mounting bolts
   Remove the mounting bolts securing the throttle body to the intake manifold. There are typically 4 bolts arranged in a square pattern. Keep track of bolt locations as some may be different lengths. Set bolts aside in a clean area.
   Torque spec

   Mounting Bolts54 Nm (40 lb-ft)
5. 5

   Remove throttle body assembly
   Carefully pull the throttle body straight away from the intake manifold. There may be a gasket or O-ring seal that will need to be replaced. Do not allow the old gasket material to fall into the intake manifold opening. Cover the intake manifold opening with a clean shop towel to prevent debris entry.
   ⚠Do not allow any debris, tools, or gasket material to fall into the open intake manifold as this can cause serious engine damage
6. 6

   Clean mating surfaces
   With the throttle body removed, thoroughly clean both the throttle body mounting flange and the intake manifold mating surface. Use brake cleaner and shop towels to remove all old gasket material, carbon deposits, and debris. Ensure surfaces are completely clean and dry before proceeding. Inspect throttle plate and bore for carbon buildup and clean if necessary.
   Torque spec

   Gasket Surface Bolts23 Nm (17 lb-ft)
7. 7

   Install new gasket and position new throttle body
   Place the new gasket or O-ring onto the intake manifold mating surface, ensuring proper alignment with bolt holes and passages. If equipped with alignment pins, verify they are seated correctly. Position the new throttle body assembly onto the gasket, aligning all bolt holes. Ensure the throttle plate is in the closed position.
8. 8

   Install and torque mounting bolts
   Install all throttle body mounting bolts hand-tight in a crisscross pattern to ensure even seating of the gasket. Using a torque wrench, tighten the mounting bolts to specification in a crisscross sequence to prevent warping the throttle body flange. Make two passes: first to half torque, then to final specification.
   Torque spec

   Mounting Bolts54 Nm (40 lb-ft)
9. 9

   Reconnect intake air duct
   Slide the intake air duct back onto the throttle body inlet, ensuring it is fully seated. Tighten the hose clamp securely but do not over-tighten. Reconnect any breather hoses that were removed. Verify all connections are secure.
10. 10

    Reconnect electrical connector
    Push the electrical connector onto the throttle body until you hear and feel a distinct click indicating it is fully seated. Gently tug on the connector to verify it is locked in place. Ensure no wires are pinched or stressed.
11. 11

    Reinstall engine cover and reconnect battery
    Align engine cover with mounting grommets and press down firmly until all clips engage with audible clicks. Reconnect the negative battery terminal and tighten securely. Reset clock and radio presets as needed.

Reassembly

1. Verify all electrical connectors are fully seated and locked
2. Ensure no tools or shop towels were left in the engine compartment
3. Double-check that all hose clamps and fasteners are tight
4. Confirm engine cover is properly installed and secured

Verification

• Start the engine and allow it to idle. The engine may run rough for the first 30 seconds as the ECU relearns idle parameters
• Verify there are no vacuum leaks by listening for hissing sounds around the throttle body
• Check for diagnostic trouble codes using an OBD-II scanner and clear any stored codes related to throttle position or idle control
• Test drive the vehicle and verify smooth idle, proper throttle response, and no hesitation during acceleration
• After initial test drive, allow engine to reach operating temperature and verify idle speed is stable between 600-800 RPM in Park/Neutral
• The ECU may require a drive cycle of 15-20 minutes to fully relearn idle characteristics

More procedures for this vehicle