Battery

This procedure covers the removal and replacement of the main 12V battery located in the trunk/boot area of the 2007-2013 Mercedes-Benz S65 AMG.

Warnings

Tools required

Parts

• 12V AGM Battery × 1 — Group 49 AGM, 850+ CCA, Use OEM specification A000982080826 or equivalent

Preparation

1. Ensure all windows are up and vehicle doors are unlocked
2. Turn ignition off and remove key from vehicle
3. Open trunk and remove carpeted floor panel on right side to access battery compartment
4. If using a battery memory saver, connect it to the 12V power outlet before disconnecting battery
5. Take note of any wiring harness routing and connector positions for reassembly

Procedure

1. 1

   Remove battery compartment cover
   Remove the plastic cover over the battery by releasing the retaining clips or removing mounting screws. Set cover aside in a clean area.
2. 2

   Disconnect negative battery terminal
   Using a 10mm socket, loosen the negative (-) terminal bolt. Do not remove the bolt completely, just loosen it enough to remove the cable. Carefully pull the negative cable off the battery post and secure it away from the battery to prevent accidental contact.
   ⚠Never allow the negative cable to contact the battery post or any positive connections once removed.
   Torque spec

   Battery Terminal Bolts6 Nm (4 lb-ft)
3. 3

   Disconnect positive battery terminal
   Using a 10mm socket, loosen the positive (+) terminal bolt. Carefully remove the positive cable from the battery post. Note that there may be a protective cover over the positive terminal that must be lifted first.
   Torque spec

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

   Remove battery vent hose
   Disconnect the battery vent hose from the side of the battery by carefully pulling it off. This hose vents battery gases to the exterior of the vehicle.
5. 5

   Remove battery hold-down bracket
   Using a 10mm or 13mm socket (depending on application), remove the battery hold-down bolt and bracket that secures the battery to the tray. Keep hardware organized for reinstallation.
   Torque spec

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

   Remove old battery
   Carefully lift the battery straight up and out of the battery tray. AGM batteries are heavy (approximately 60 lbs). Use proper lifting technique and get assistance if needed. Inspect the battery tray for corrosion or debris.
   ⚠Battery weighs approximately 60 lbs (27 kg). Use proper lifting technique to avoid injury.
7. 7

   Clean battery tray and terminals
   Use a wire brush to clean any corrosion from the battery tray and cable terminals. Wipe the tray clean with a dry cloth. Ensure no debris or corrosion remains that could affect electrical connections.
8. 8

   Install new battery
   Place the new battery into the battery tray, ensuring it is oriented correctly with positive terminal in the correct position (typically toward the front of the vehicle). The battery should sit flush in the tray.
9. 9

   Install battery hold-down bracket
   Position the hold-down bracket over the battery and install the hold-down bolt. Torque the bolt to specification. Ensure the battery is secure and cannot move.
   Torque spec

   Battery Hold-Down Bolt8 Nm (6 lb-ft)
10. 10

    Reconnect battery vent hose
    Connect the battery vent hose to the fitting on the side of the battery. Ensure it is fully seated and secure.
11. 11

    Connect positive battery terminal
    Place the positive cable onto the positive battery post. Apply a small amount of dielectric grease to the connection if desired. Install and tighten the terminal bolt to specification using a 10mm socket and torque wrench. Do not overtighten.
    ⚠Do not exceed specified torque. Overtightening can damage the battery post or terminal.
    Torque spec

    Battery Terminal Bolts6 Nm (4 lb-ft)
12. 12

    Connect negative battery terminal
    Place the negative cable onto the negative battery post. Install and tighten the terminal bolt to specification using a 10mm socket and torque wrench. Do not overtighten.
    ℹ️Upon reconnection, various warning lights may illuminate. This is normal and most will clear after a short drive cycle.
    Torque spec

    Battery Terminal Bolts6 Nm (4 lb-ft)
13. 13

    Reinstall battery compartment cover
    Replace the plastic battery cover and secure with clips or screws. Ensure all wiring is properly routed and not pinched by the cover.

Reassembly

1. Replace trunk floor carpeted panel
2. Verify all trunk components are properly secured
3. Remove battery memory saver if used

Verification

• Turn ignition to position II and verify all electrical systems activate (gauges, lights, displays)
• Start the engine and verify it cranks normally and starts without hesitation
• Check for any warning lights on the instrument cluster that do not clear after 30 seconds
• Verify power windows, mirrors, seats, and other electrical accessories function properly
• Test door locks and remote key fob operation
• Allow vehicle to idle for 2-3 minutes to begin ECU relearning process
• Reset clock and restore radio presets if battery memory saver was not used
• If anti-theft radio lockout occurred, enter radio code per owner's manual instructions
• Take vehicle for a 10-15 minute test drive to allow transmission and engine ECU to relearn adaptive values

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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