This procedure covers the removal and replacement of the air injection check valve on the 2019-2024 Toyota RAV4 2.5L I4 engine, which prevents backflow in the secondary air injection system.

Warnings

Tools required

Parts

• Air injection check valve × 1 — Use OEM specification
• Check valve gasket × 1 — Use OEM specification

Preparation

1. Ensure engine and exhaust system are completely cool to the touch
2. Park vehicle on level surface and engage parking brake
3. Disconnect negative battery terminal and wait 2 minutes for system capacitors to discharge
4. Remove engine cover by pulling upward on four retention points

Procedure

1. 1

   Access the check valve area
   The air injection check valve is located on the exhaust manifold near the front of the engine. Remove any interfering upper engine covers or shields. On some models, you may need to remove the engine splash shield from below for better access. Use panel removal tools to avoid breaking clips.
2. 2

   Disconnect electrical connector
   Locate the air injection pump connector if equipped. Press the release tab and disconnect the electrical connector. Move wiring harness aside to provide clearance.
3. 3

   Remove air injection hoses
   Disconnect the air supply hose from the check valve by loosening the hose clamp with a flathead screwdriver or removing the quick-connect fitting. Note the orientation of the hose routing for reassembly. Remove the hose from the check valve inlet port.
4. 4

   Remove heat shield if present
   If a heat shield is covering the check valve mounting area, remove the retaining bolts using a 10mm socket. Set the heat shield aside. Keep all hardware organized for reinstallation.
   Torque spec

   Heat Shield Bolts10 Nm (7 lb-ft)
5. 5

   Remove check valve mounting bolts
   Using a 12mm or 14mm socket (verify size before applying force), remove the two or three mounting bolts securing the check valve to the exhaust manifold or cylinder head. The valve is typically mounted with a flange connection. Support the valve as you remove the final bolt.
6. 6

   Remove check valve assembly
   Carefully pull the check valve away from the mounting surface. The valve may be stuck due to carbon buildup or gasket adhesion. Gently wiggle while pulling if necessary. Remove and discard the old gasket from both mating surfaces.
   ⚠Do not pry against the exhaust manifold flange as this may cause warping or damage to sealing surfaces.
7. 7

   Clean mounting surfaces
   Use a wire brush and shop towels to thoroughly clean both the exhaust manifold mounting surface and the check valve mounting flange (if reusing components). Remove all old gasket material, carbon deposits, and debris. The surface must be clean and flat for proper sealing.
8. 8

   Inspect check valve operation
   If reusing the check valve, blow through it in both directions to verify one-way operation. Air should flow freely in one direction and be completely blocked in the reverse direction. If air flows both ways or is blocked in both directions, the valve has failed and must be replaced.
9. 9

   Install new gasket and check valve
   Position the new gasket on the exhaust manifold mounting surface. Align the check valve with the mounting holes, ensuring the flow direction arrow points toward the exhaust manifold. Start all mounting bolts by hand to ensure proper thread engagement before tightening.
10. 10

    Torque mounting bolts
    Tighten the check valve mounting bolts to 27.0 Nm (20.0 lb-ft) in a criss-cross pattern to ensure even gasket compression and prevent leaks. Verify that the valve sits flush against the mounting surface with no gaps.
    Torque spec

    Mounting Bolts27 Nm (20 lb-ft)
11. 11

    Reinstall heat shield
    If a heat shield was removed, position it back in place and install the retaining bolts. Tighten the heat shield bolts to 10.0 Nm (7.0 lb-ft). Ensure the shield does not contact or restrict any hoses or wiring.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)
12. 12

    Reconnect air supply hose
    Reconnect the air supply hose to the check valve inlet port. Ensure the hose is fully seated and secure the hose clamp or quick-connect fitting. Verify the hose routing matches the original configuration and does not contact hot exhaust components.
13. 13

    Reconnect electrical connections
    Reconnect the air injection pump electrical connector if it was disconnected. Ensure the connector clicks into place and the locking tab is fully engaged. Route all wiring away from hot exhaust components.

Reassembly

1. Reinstall engine cover by aligning mounting points and pressing down firmly until all clips engage
2. Reinstall any splash shields removed during access, ensuring all clips and fasteners are secure
3. Reconnect negative battery terminal and tighten securely

Verification

• Start the engine and listen for any unusual hissing or exhaust leaks from the check valve area
• Allow engine to reach operating temperature and verify no exhaust odors or visible leaks around the check valve
• Use an OBD-II scanner to verify no air injection system fault codes are present (P0410, P0411, P0412)
• During cold start, the air injection pump should operate for 60-120 seconds - listen for pump operation and verify smooth engagement
• Perform a test drive and verify check engine light does not illuminate

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