When the battery is disconnected, any fault codes stored in the engine management ECM memory will be erased. If any faults are suspected, do not disconnect the battery until the fault codes have been read by a BMW dealer or specialist. If the vehicle is fitted with a code-protected audio unit, refer to the Owners handbook.
The battery is located beneath a cover on the right-hand side of the luggage compartment.
On Saloon models, lift the catch, and remove the left-hand side luggage compartment side trim above the battery
. On Touring models, lift out the luggage compartment floor panel, undo the two fasteners and lift out the side panel, then rotate the two fasteners 90° anti-clockwise and lift out the trim above the battery
Rotate the catch and lift out the panel – Saloon models
Lift the handle and remove the luggage compartment floor panel
Rotate the fasteners 90° . . .
. . . and lift the base of the panel inwards to remove it
Rotate the fasteners 90° . . .
. . . and lift the panel above the battery
Slacken the clamp nut, and disconnect the clamp from the battery negative (earth) terminal
. Position the negative lead away from the battery, so there is no risk of accidental contact between it and the battery terminal. For extra protection, cover the disconnected lead clamp with a rag or rubber glove, etc.
Slacken the nut and disconnect the negative lead clamp
Disconnect the battery negative lead as described previously.
Undo the 2 bolts and remove the support bracket above the battery
Undo the 2 bolts and remove the bracket above the battery
Prise up the plastic cover, and undo the nut securing the connector assembly to the positive clamp
Prise up the cover, undo the nut . . .
Using a flat-bladed screwdriver, lever apart the retaining clip each side and lift up the connector assembly from the top of the battery
. Position the connector assembly to one side.
. . . lever apart the retaining clip each side . . .
. . . and lift off the connector assembly
Prise up the plastic cover, slacken the nut and pull the positive clamp assembly from the terminal on the battery
Prise up the plastic cover, slacken the nut . . .
. . . and pull up the positive clamp
Unscrew the bolt, and remove the battery retaining clamp
Undo the bolt and remove the battery retaining clamp
Lift the battery from its housing, disconnect the vent hose as the battery is removed
. Take care as the battery is heavy.
Pull the vent hose from the side of the battery . . .
. . . and lift it from place
Refitting is a reversal of removal. Always reconnect the positive lead first, and the negative lead last.
After reconnecting the battery, several of the vehicles ECMs will require time to relearn certain values. This will normally be complete within a normal driving pattern of 15 miles (approximately). In addition, several systems may require re-initialisation as follows:
- With the battery reconnected, and the ignition on, press the sunroof operating switch into the ‘tilt’ position and hold it there.
- Once the sunroof has reached the ‘fully-tilted’ position, hold the switch in that position for approximately 20 seconds. Initialisation is complete, when the sunroof briefly lifts at the rear again.
- Operate the button to fully close the window, then continue to hold the button for at least 1 second to ‘normalise’ the anti-trapping function.
If a new battery has been installed, the new battery details may need be registered in the vehicles ECM using BMW diagnostic equipment (or equivalent) to enable off the convenience system/functions to operate correctly. Entrust this task to a BMW dealer or suitably equipped specialist.