Battery

Replace the 12V battery in a 2009 Aston Martin DB9, including access to the trunk-mounted battery, disconnection, and installation with proper torque specifications.

Warnings

Tools required

Parts

• 12V battery × 1 — Group 49 AGM battery, 90Ah minimum (OEM: Varta or equivalent)
• Battery terminal anti-corrosion washers (if deteriorated) × 2 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake.
2. Ensure ignition is off and key fob is at least 10 feet away from vehicle to prevent inadvertent module wake-up.
3. Open trunk and locate battery access panel on driver-side trunk interior trim.
4. If using a memory saver, connect it now per manufacturer instructions before disconnecting battery.

Procedure

1. 1

   Remove trunk trim access panel
   Locate the trunk-side trim panel on the driver side of the trunk. Remove the fasteners securing the trim panel to access the battery compartment. The panel is typically held by plastic push-clips and Torx fasteners around the perimeter. Carefully pull the panel away once fasteners are removed to expose the battery and hold-down hardware.
2. 2

   Disconnect negative battery terminal
   Locate the negative (-) battery terminal, marked with a minus sign or black cover. Using the appropriate socket (verify fastener size against Aston Martin service documentation), loosen the terminal bolt by turning counterclockwise. Do not fully remove the bolt unless necessary - typically 3-4 turns is sufficient to release terminal pressure. Lift the negative cable terminal off the battery post and secure it away from the battery to prevent accidental contact. If terminal is seized due to corrosion, use a battery terminal puller.
3. 3

   Disconnect positive battery terminal
   Locate the positive (+) battery terminal, marked with a plus sign or red cover. Using the appropriate socket (verify fastener size against Aston Martin service documentation), loosen the terminal bolt by turning counterclockwise. Lift the positive cable terminal off the battery post and ensure it does not contact any metal surfaces or the negative terminal.
4. 4

   Remove battery hold-down clamp
   Locate the battery hold-down bracket at the base of the battery. Using the appropriate socket and extension (verify fastener size on vehicle), remove the hold-down bolt securing the clamp. The bolt threads into the battery tray beneath the battery. Lift the hold-down clamp away once the bolt is fully removed. Note: Using the appropriate socket and extension (verify size against OEM spec), remove the hold-down bolt/bracket securing the battery. Note: Using the appropriate socket and extension (verify fastener size against service documentation), remove the hold-down bolt securing the clamp.
   Torque spec

   Battery Hold-Down Bolt8 Nm (6 lb-ft)
5. 5

   Remove battery from tray
   Carefully lift the battery straight up and out of the battery tray. The battery is heavy (verify actual weight for the correct battery specification), so use proper lifting technique. Inspect the battery tray for corrosion, debris, or acid residue. Clean the tray with a wire brush and baking soda solution if corrosion is present, then dry thoroughly.
6. 6

   Inspect and clean battery terminals and cables
   Inspect both battery cable terminals for corrosion, cracks, or damage. Clean the inside of both cable terminals using a wire brush or battery terminal cleaner until bare metal is visible. Inspect cable insulation for cracking or damage. If terminals or cables are damaged, they must be replaced before installing the new battery.
7. 7

   Install new battery
   Place the new battery into the battery tray, ensuring it is oriented correctly so each terminal matches its corresponding cable position (verify orientation against the removed battery and cable routing). Ensure the battery sits fully flush in the tray with no rocking or gaps. Note: Place the new battery into the battery tray, ensuring it is oriented identically to the battery that was removed so the positive and negative terminals align with their respective cables. Note: Place the new battery into the battery tray, ensuring it is oriented correctly so the positive terminal matches the positive cable position (verify correct terminal orientation against the original battery before installation).
8. 8

   Install battery hold-down clamp
   Position the hold-down clamp over the top of the battery, aligning the bracket with the threaded mounting hole in the battery tray. Thread the hold-down bolt through the clamp and into the tray, tightening by hand first to ensure proper thread engagement. Torque the bolt to the manufacturer-specified value (confirm hold-down bolt torque in Aston Martin service documentation) using a torque wrench. The clamp should hold the battery firmly without deforming the battery case. Note: Torque the bolt to the manufacturer-specified value (verify hold-down bolt torque against Aston Martin service documentation) using a torque wrench.
   Torque spec

   Battery Hold-Down Bolt8 Nm (6 lb-ft)
9. 9

   Connect positive battery terminal
   Place the positive (+) cable terminal onto the positive battery post, ensuring it seats fully onto the post with maximum contact. If using dielectric grease, apply a small amount to the post before installing the terminal. Using the correct socket (verify fastener size) and a torque wrench, tighten the terminal bolt to the manufacturer-specified torque. Do not overtighten as this can crack the terminal clamp or damage the battery post.
   Torque spec

   Battery Terminal Bolts6 Nm (4 lb-ft)
10. 10

    Connect negative battery terminal
    Place the negative (-) cable terminal onto the negative battery post, ensuring it seats fully onto the post. Using the appropriate socket (verify fastener size against Aston Martin service documentation) and torque wrench, tighten the terminal bolt to specification. Do not overtighten as this can crack the terminal clamp or damage the battery post. Expect a small spark when final connection is made as vehicle modules initialize - this is normal.
    Torque spec

    Battery Terminal Bolts6 Nm (4 lb-ft)
11. 11

    Reinstall trunk trim panel
    Position the trunk trim access panel back into place, aligning all mounting points. Install all Torx fasteners and push-clips in reverse order of removal, ensuring the panel sits flush with no gaps or rattles.
12. 12

    Initialize vehicle systems
    Insert the ECU (Emotion Control Unit) glass key into the dash slot and press to place the vehicle in ignition-on mode without cranking the engine (verify correct ignition-on procedure against Aston Martin service documentation). Allow the vehicle to sit for 30 seconds to initialize all control modules. If equipped with one-touch/auto window function, perform the window reinitialization per the Aston Martin factory procedure (sequence and hold times vary); verify against service documentation. Repeat for all windows. Check that radio, clock, and other settings are retained or require resetting.

Reassembly

1. Reassembly is included in the procedure steps above.
2. Ensure all trunk trim panels are secure and properly seated to prevent rattles.
3. Verify battery terminals are tight and cannot be rotated by hand on the battery posts.

Verification

• Start the engine and verify normal starting behavior with no warning lights remaining illuminated after startup.
• Test all electrical accessories: lights, windows, climate control, radio, navigation, and instrument cluster for proper function.
• Verify power window auto-up/down function operates correctly on all windows after reinitialization.
• Check for any stored diagnostic trouble codes using an OBD-II scanner; clear any codes related to low voltage during battery replacement.
• Ensure trunk trim panel is secure with no rattles or loose fasteners.

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