Battery Cables - Both

Complete replacement of both positive and negative battery cables on the 2009 Aston Martin DB9, including removal of trunk components for access, cable routing through chassis, and connection at battery and engine ground points.

Warnings

Tools required

Parts

• Positive battery cable assembly × 1 — Use OEM specification
• Negative battery cable assembly × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Open trunk and locate battery on right side of trunk compartment
3. Ensure all electrical accessories are off
4. Have radio security code available if applicable
5. Allow engine to cool completely if recently driven

Procedure

1. 1

   Disconnect battery negative terminal
   Using the appropriate socket (verify size against OEM spec), loosen the negative battery terminal bolt. Remove the negative cable from the battery post and secure it away from the battery to prevent accidental contact. Wait the manufacturer-specified time (typically several minutes; verify in service documentation) for airbag system capacitors to discharge before proceeding.
2. 2

   Disconnect battery positive terminal
   Using the appropriate socket (verify size against OEM spec), loosen the positive battery terminal bolt. Remove the positive cable from the battery post. Cover the terminal end with a non-conductive material or secure it away from any metal surfaces.
3. 3

   Remove trunk side trim panel
   On the right side of the trunk where the battery is located, identify and remove the trunk side trim panel. Remove the Torx fasteners securing the panel (typically T20 or T30). Carefully pull the panel away from the body, releasing any clips. This provides access to cable routing behind the trim.
4. 4

   Trace and document cable routing
   Before removing cables, trace the routing path of both positive and negative cables from the battery through the trunk floor and into the engine compartment. Note the location of any cable securing clips, grommets, and routing channels. Take photos if possible to ensure correct reinstallation routing.
5. 5

   Remove battery hold-down if necessary
   If the battery hold-down bracket interferes with cable removal, use the appropriate socket (verify fastener size) to remove the battery hold-down bolt. Remove the hold-down clamp and set aside. The battery can remain in place but will be easier to work around if hold-down is removed. Note: If the battery hold-down bracket interferes with cable removal, remove the battery hold-down bolt using the correct socket size (verify fastener size/type on the vehicle before loosening). Note: If the battery hold-down bracket interferes with cable removal, remove the battery hold-down bolt using the correct socket size (verify fastener size on the vehicle; commonly 10mm or 13mm).
   Torque spec

   Battery Hold-Down Bolt15 Nm (11 lb-ft)
6. 6

   Disconnect positive cable at starter or junction
   Open the engine hood. Locate where the positive battery cable terminates at the main power distribution junction (fuse/relay box) — confirm the exact termination point from the vehicle wiring diagram, as it may not route directly to the starter. Remove the protective cover if present. Use the appropriate socket (verify size against OEM spec) to remove the fastening nut securing the positive cable terminal. Remove the cable terminal and note the exact position and any other cables or wires sharing the stud. Note: Locate where the positive battery cable terminates at the main power distribution box / engine compartment fuse box junction (verify exact termination point against Aston Martin service documentation; it is not a direct starter-motor connection on this vehicle). Note: Locate where the positive battery cable terminates at the engine bay power distribution point (near the fuse/relay box) and/or the starter motor solenoid; confirm the exact termination point against the Aston Martin DB9 workshop manual before disconnecting.
7. 7

   Remove positive cable from vehicle
   Working from both engine bay and trunk, release any cable tie points or clips securing the positive cable along its route. Carefully withdraw the cable through the firewall grommet and trunk routing channels. Remove the cable completely from the vehicle, noting the grommet location for reinstallation.
8. 8

   Disconnect negative cable at engine ground points
   In the engine bay, locate the negative cable ground connection points. The primary ground is typically bolted to the engine block or transmission bellhousing, with a secondary ground strap to the body. Use the appropriate socket (verify fastener size against OEM spec) to remove the ground cable bolts at each connection point. Note the exact mounting location and orientation of ground terminals.
   Torque spec

   Ground Cable Bolt10 Nm (7 lb-ft)

   Ground Strap Bolts12 Nm (9 lb-ft)
9. 9

   Remove negative cable from vehicle
   Release any securing clips or ties along the negative cable route. Carefully withdraw the cable through the routing channels from engine bay to trunk. Remove the cable completely, preserving any grommets or protective sleeves for reuse.
10. 10

    Clean all connection points
    Using wire brush or battery terminal cleaner, thoroughly clean the battery posts, all cable terminal ends on the new cables, engine ground mounting points on the block and body, and the starter or junction stud where positive cable connects. Remove all corrosion, oxidation, and dirt. Spray with electrical contact cleaner and allow to dry. Clean contact surfaces are critical for proper electrical conductivity.
11. 11

    Route and install new negative cable
    Begin at the battery end. Route the new negative cable through the same path as the original, from trunk through to engine bay. Ensure the cable passes through any grommets correctly and is not kinked or pinched. Install the cable end at the engine block ground point first, then at any secondary body ground points. Do not fully tighten yet. Secure cable with any clips or ties along the routing path.
12. 12

    Route and install new positive cable
    Route the new positive cable from battery through trunk and firewall grommet to engine bay, following the exact original path. Ensure proper grommet seating at firewall penetration. Route to the starter motor or power distribution junction. Connect the terminal to the stud in the same orientation as original, with any shared terminals in correct order. Do not fully tighten yet. Secure cable routing with clips or ties.
13. 13

    Torque engine bay connections
    Using torque wrench, tighten the negative cable ground bolt at engine block and any secondary ground strap bolts to the Aston Martin specified torque values (verify exact figures in factory service documentation; do not assume). Tighten the positive cable connection at the power distribution junction to the Aston Martin specified torque (verify exact value in factory service documentation before final tightening). Ensure all connections are tight and terminals cannot rotate. Note: Using a torque wrench, tighten the negative cable ground bolt(s) and any secondary ground strap bolts to the Aston Martin OEM-specified torque (verify from service documentation). Tighten the positive cable connection at the power distribution junction to OEM specification. Note: Using a torque wrench, tighten the negative cable ground bolt(s) and any secondary ground strap bolts to the Aston Martin DB9 specified torque. Tighten the positive cable connection at the power distribution/starter stud to the manufacturer-specified torque. Verify all torque values against the official Aston Martin DB9 workshop manual before tightening.
    Torque spec

    Ground Cable Bolt10 Nm (7 lb-ft)

    Ground Strap Bolts12 Nm (9 lb-ft)
14. 14

    Connect positive terminal to battery
    At the battery in the trunk, place the positive cable terminal onto the positive battery post. Apply a light coating of dielectric grease to the connection if desired. Thread the terminal bolt and tighten to the Aston Martin specified battery terminal torque (verify exact value in factory service documentation) using a torque wrench. Do not overtighten as this can damage the terminal or post. Note: Thread the terminal bolt and tighten to the OEM-specified battery terminal torque (verify from service documentation) using a torque wrench. Note: Thread the terminal bolt and tighten to the Aston Martin DB9 specified battery terminal torque using a torque wrench (verify value against the OEM workshop manual).
    Torque spec

    Battery Terminal Bolts6 Nm (4 lb-ft)
15. 15

    Connect negative terminal to battery
    Place the negative cable terminal onto the negative battery post. Thread the terminal bolt and tighten to the Aston Martin specified battery terminal torque (verify exact value in factory service documentation) using a torque wrench. The connection of this terminal will restore power to the vehicle. Note: Place the negative cable terminal onto the negative battery post. Thread the terminal bolt and tighten to the OEM-specified battery terminal torque (verify from service documentation) using a torque wrench. Note: Thread the terminal bolt and tighten to the Aston Martin DB9 specified battery terminal torque using a torque wrench (verify value against the OEM workshop manual).
    Torque spec

    Battery Terminal Bolts6 Nm (4 lb-ft)
16. 16

    Reinstall battery hold-down and trim
    If battery hold-down was removed, reinstall the hold-down clamp and tighten the bolt to the OEM-specified torque (verify from service documentation). Reinstall the trunk side trim panel, securing all Torx fasteners and ensuring all clips are properly engaged. Verify no cables are pinched by trim panel. Note: If battery hold-down was removed, reinstall the hold-down clamp and tighten the bolt to the Aston Martin specified torque (verify exact value in factory service documentation; typically a low value to avoid damaging the battery case). Note: If battery hold-down was removed, reinstall the hold-down clamp and tighten the bolt to the Aston Martin DB9 specified torque (verify value against the OEM workshop manual; do not overtighten, as excessive force can damage the battery case).
    Torque spec

    Battery Hold-Down Bolt15 Nm (11 lb-ft)

Reassembly

1. Verify all trunk trim panels are securely fastened and properly aligned
2. Ensure no tools or parts remain in trunk or engine bay
3. Check that all cable routing is secure and clear of moving components or heat sources

Verification

• Turn ignition to ON position (do not start) and verify dashboard lights illuminate normally
• Start the engine and verify it cranks normally with strong starter engagement
• Check that all electrical systems function correctly (lights, windows, radio, climate control)
• Visually inspect all cable connections for tightness and proper seating
• Verify no warning lights remain illuminated on dashboard after 30 seconds of engine running
• Check battery voltage with multimeter: should read 12.4-12.8V key off, 13.8-14.4V engine running
• Re-enter radio security code if required and reset clock/vehicle settings

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