EVAP Vent Valve

This procedure replaces the EVAP vent valve on a 2009 Aston Martin DB9, which controls the purging of fuel vapors from the evaporative emissions system.

Warnings

Tools required

Parts

• EVAP vent valve × 1 — Use OEM specification
• EVAP vent valve O-ring seal (if separate) × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground and engage parking brake.
2. Turn ignition to OFF position and remove key.
3. Allow engine to cool if vehicle was recently operated.
4. Gather all tools and replacement parts before beginning work.

Procedure

1. 1

   Disconnect battery negative terminal
   Access the battery (on the 2009 DB9 the battery is typically located in the trunk/boot area — verify exact location and access panel per Aston Martin service documentation). Using the appropriate socket, loosen and remove the negative battery terminal. Isolate the terminal to prevent accidental reconnection during the procedure. Note: Access the battery (located in the luggage compartment/trunk area on the DB9; verify exact location and remove any covering trim). Using the appropriate socket, loosen and remove the negative battery terminal. Isolate the terminal to prevent accidental reconnection during the procedure. Note: Open the trunk and access the battery compartment, which on the DB9 is located behind the trunk trim panel (verify exact location and access panel per Aston Martin service documentation).
2. 2

   Raise and secure left rear of vehicle
   Lift the left rear corner of the vehicle using a floor jack at the designated jacking point. Support the vehicle securely on a jack stand rated for the vehicle weight. Ensure the vehicle is stable before working underneath.
3. 3

   Remove left rear wheel
   Remove the left rear wheel lug nuts and remove the wheel to access the wheel well liner. Set the wheel aside in a safe location.
4. 4

   Access wheel well liner
   Locate the wheel well liner fasteners along the rear edge and underside. Remove the fasteners securing the rear section of the liner (these may be Torx screws, plastic push-rivets/clips, or a combination). The exact number, type, and location of wheel well liner fasteners for the 2009 DB9 must be verified against Aston Martin service documentation before proceeding. Carefully pull the liner back to expose the EVAP system components without completely removing it.
5. 5

   Locate EVAP vent valve
   With the liner pulled back, identify the EVAP vent valve near the charcoal canister assembly (verify exact mounting location against Aston Martin service documentation for the 2009 DB9). The valve is a cylindrical component with an electrical connector and vapor hoses attached. Use a work light to clearly see the component and its connections.
6. 6

   Disconnect electrical connector
   Locate the electrical connector on the EVAP vent valve. Press the release tab on the connector and carefully pull it straight off the valve. Do not pull on the wires themselves. If the connector is difficult to access, use a small pick to depress the locking tab.
7. 7

   Disconnect vapor hoses
   Identify the vapor hose(s) connected to the EVAP vent valve (verify exact number and routing against Aston Martin documentation for the 2009 DB9). Note their orientation for reinstallation. Release the hose clamps or quick-disconnect fittings securing each hose. If equipped with spring clamps, use pliers to compress and slide them back along the hose. If equipped with quick-disconnect fittings, press the release tabs and pull the hoses straight off. Some fuel vapor may be present in the lines; use shop towels to catch any residual vapors or condensation.
8. 8

   Remove EVAP vent valve mounting fasteners
   Locate the mounting bracket or fasteners securing the EVAP vent valve to its mounting location. Remove the fasteners holding the valve bracket to the body (exact count, size, and fastener type must be verified against Aston Martin service documentation for the 2009 DB9). Keep these fasteners organized for reinstallation.
9. 9

   Remove old EVAP vent valve
   With all connections and fasteners removed, carefully extract the EVAP vent valve from its mounting location. Maneuver it out through the wheel well opening. Inspect the old valve for signs of damage, corrosion, or contamination.
10. 10

    Prepare new EVAP vent valve
    Remove the new EVAP vent valve from its packaging. Inspect the valve for any shipping damage. If the valve includes a separate O-ring seal, verify it is properly seated in the valve body groove. If lubrication is specified by the manufacturer, use only an EVAP-safe O-ring lubricant (do not use engine oil, as petroleum products can degrade EVAP seals). Note: If lubrication is specified by the manufacturer, use only an EVAP-compatible silicone-based lubricant on the O-ring; do not use petroleum-based engine oil, which can degrade the seal and contaminate the vapor system. Note: Lightly lubricate the O-ring with a fuel-system-compatible lubricant (such as clean silicone grease) only if specified by the manufacturer.
11. 11

    Install new EVAP vent valve
    Position the new EVAP vent valve into the mounting location, ensuring it is oriented correctly with the hose ports and electrical connector accessible. Install the mounting bracket and secure with the fasteners, torquing to the Aston Martin specified value (verify exact value against factory documentation — do not overtighten if threading into plastic/composite).
12. 12

    Reconnect vapor hoses
    Connect the two vapor hoses to the new EVAP vent valve in their original positions. Ensure each hose is fully seated onto the valve port. Reinstall or reposition the hose clamps, ensuring they are positioned over the connection area. If equipped with quick-disconnect fittings, push the hoses on until you hear or feel a click indicating the lock has engaged. Tug gently on each hose to verify secure connection.
    Torque spec

    Hose Clamps3 Nm (2 lb-ft)
13. 13

    Reconnect electrical connector
    Plug the electrical connector onto the new EVAP vent valve, ensuring it seats fully and the locking tab engages with an audible click. Verify the connection is secure by gently tugging on the connector body.
14. 14

    Reinstall wheel well liner
    Reposition the wheel well liner to its original location. Install all Torx fasteners in their original locations, working from one end to the other to ensure even seating. Verify the liner is flush and does not interfere with any suspension or brake components.
15. 15

    Reinstall wheel and lower vehicle
    Reinstall the left rear wheel and hand-tighten the lug nuts in a star pattern. Lower the vehicle from the jack stand and remove the jack. Torque the wheel bolts (the DB9 uses bolts threading into the hub, not lug nuts on studs) to the Aston Martin specified value (verify exact figure against factory documentation — commonly approximately 150 Nm / 111 lb-ft) in a star pattern. Note: Torque the wheel bolts/lug nuts to the Aston Martin specification for the 2009 DB9 in a star pattern (torque value must be verified against factory documentation).
16. 16

    Reconnect battery
    Return to the trunk and reconnect the negative battery terminal. Tighten the terminal clamp securely.
17. 17

    Clear diagnostic codes
    Using an OBD-II scan tool (an Aston Martin-capable tool may be required for full access), clear any EVAP-related diagnostic trouble codes from the engine control module. This ensures a fresh baseline for system operation verification.

Reassembly

1. Installation is the reverse of removal, following steps 10-17.
2. Ensure all hose connections are secure and clamps are properly positioned.
3. Verify the electrical connector locks into place with an audible click.

Verification

• Turn the ignition to ON position (engine off) and listen for the EVAP vent valve operating. You may hear a brief clicking or buzzing sound as the system performs a self-test.
• Start the engine and allow it to reach operating temperature. Monitor for any fuel vapor odors around the wheel well area, which would indicate a leak.
• Using an OBD-II scan tool, verify that no EVAP system diagnostic codes are present after a complete drive cycle.
• Perform an EVAP system monitor drive cycle per Aston Martin specifications (typically involves driving at various speeds and allowing the vehicle to idle) to allow the system to complete its self-tests.
• After the drive cycle, re-scan for codes. The EVAP system monitor should show 'Ready' status, confirming proper valve operation.

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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