Idle Air Control Valve

This procedure covers the removal and replacement of the Idle Air Control Valve (IACV) on the 2018-2024 Honda Accord 1.5L Turbo engine to restore proper idle control.

Warnings

Tools required

Parts

• Idle Air Control Valve × 1 — Use OEM Honda specification
• IACV gasket or O-ring × 1 — Usually included with valve

Preparation

1. Ensure engine is completely cool before beginning work
2. Park vehicle on level ground and apply parking brake
3. Disconnect negative battery terminal and wait 3 minutes before proceeding
4. Remove engine cover by pulling upward on front clips and lifting off
5. Locate the throttle body on the driver side of the intake manifold

Procedure

1. 1

   Disconnect throttle body electrical connector
   Press the locking tab on the throttle body electrical connector and carefully pull straight out to disconnect. Do not pull on the wires themselves.
2. 2

   Disconnect PCV hose and breather hose
   Locate the PCV hose and breather hose connected to the throttle body inlet. Squeeze the hose clamps and slide them back, then twist and pull the hoses off the throttle body connections. Use a flathead screwdriver if needed to break the seal.
3. 3

   Remove throttle body mounting bolts
   Remove the two throttle body mounting bolts using a 10mm socket. Support the throttle body with one hand while removing the second bolt to prevent it from falling.
   Torque spec

   Mounting Bolts45 Nm (33 lb-ft)
4. 4

   Remove throttle body assembly
   Carefully pull the throttle body straight out from the intake manifold. The gasket may stick, requiring gentle twisting motion. Do not pry against the throttle body bore or butterfly valve.
5. 5

   Inspect and clean mounting surface
   Remove the old gasket completely from both the intake manifold and throttle body surfaces. Clean both surfaces with shop towels and electrical contact cleaner. Inspect the intake manifold opening for carbon buildup and clean if necessary. Do not allow debris to fall into the manifold.
6. 6

   Inspect throttle body bore
   With the throttle body removed, inspect the butterfly valve and bore for carbon deposits. Clean if necessary using throttle body cleaner and a soft cloth. Do not force the butterfly valve open or closed during cleaning.
7. 7

   Install new gasket
   Position the new throttle body gasket onto the intake manifold mounting surface, ensuring alignment pins or bolt holes are properly seated. Verify the gasket is oriented correctly per the replacement part markings.
8. 8

   Install throttle body
   Align the throttle body with the gasket and mounting bolt holes. Gently push the throttle body into position, ensuring the gasket does not shift. Start both mounting bolts by hand to ensure proper thread engagement.
   Torque spec

   Mounting Bolts45 Nm (33 lb-ft)
9. 9

   Reconnect hoses and electrical connector
   Reconnect the PCV hose and breather hose to the throttle body, sliding the hose clamps into position. Reconnect the throttle body electrical connector until it clicks into place.
10. 10

    Reinstall engine cover and battery
    Reinstall the engine cover by aligning the rear tabs first, then pressing down firmly on the front clips until they snap into place. Reconnect the negative battery terminal.

Reassembly

1. Torque the throttle body mounting bolts to 26.0 Nm (19.0 lb-ft) in a criss-cross pattern
2. Double-check all electrical connections are fully seated and locked
3. Verify all hoses are properly secured with clamps in correct positions

Verification

• Turn ignition to ON position without starting engine; listen for throttle body motor initialization (brief whirring sound)
• Start the engine and verify it idles smoothly without stalling
• Allow engine to reach operating temperature and confirm idle speed stabilizes between 600-800 RPM
• Test drive vehicle and verify smooth acceleration with no hesitation or rough idle at stops
• Check for vacuum leaks around throttle body gasket by listening for hissing sounds while engine idles
• Use a scan tool to verify no throttle body or idle control DTCs are present

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

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