Disconnecting all battery ground leads
Remove flap in luggage compartment trim panel on right
Remove flap in luggage compartment trim panel on right
Remove right luggage compartment trim panel
- Remove the cover (1) to the top.
- Remove the cover (2) to the inside.
- Remove the luggage compartment trim panel (1) to the top.
De-energize the high-voltage system
Precondition
Trunk lid is open.
Ignition is switched off.
Vehicle has gone to sleep (rest state).
Risk of short circuits! Risk of fire!
- Make sure that there is no charging cable connected.
- Make sure that there is no charger connected to the jump start terminal in the engine compartment.
- For vehicles with additional electrical systems (48 V electrical system, high-voltage vehicle electrical system), this absolutely must be deactivated before the vehicle battery is disconnected.
The high-voltage safety disconnect cannot be fully disconnected.
- Unlock and pull out the high-voltage safety plug (1) until the bore (2) on the connector and the connector are fully exposed.
The OFF labeling on the high-voltage safety plug is visible.
- Insert the shackle lock (1) into the exposed bore (2) on the high-voltage safety plug (3) and lock it.
- Store the shackle lock key in a safe place.
Check that no voltage is applied
Precondition
Mortal hazard if the disconnection from power cannot be verified!
- Make sure that the Check Control message "High-voltage system deactivated" is displayed in the instrument cluster before commencing work.
- Lock the vehicle and block it with high-voltage barrier tape if the disconnection from power cannot be clearly verified.
- Contact Technical Support in all cases where the disconnection from power is not clearly verified.
- A certified qualified electrician 1000 V DC must verify the disconnection from power with measuring devices/measuring procedures.
Zero voltage (high-voltage system switched-off) is only displayed with in PAD mode.
Check
- Press the START-STOPPING button quickly 3 times without stepping on the brake pedal to establish the PAD mode.
Check that the instrument cluster (KOMBI) is de-energized in PAD mode.
Desired state
- The "High-voltage system switched off" Check Control message must be displayed.
Result
» If it cannot be determined with certainty that the instrument cluster (KOMBI) is de-energized , work must not begin. Mortal hazard!
Measure
- Before work begins, a qualified and certified electrician (1000 V DC) must verify that the system has been de-energized using appropriate measuring devices and measuring procedures.
The 12 V vehicle battery must not be disconnected until the "High-voltage system switched off" Check Control message is displayed in the instrument cluster (KOMBI).
If the Check Control message is not displayed, the "De-energize the high-voltage system Read out prevention reasons" service function can be executed.
- Service functions > Electric drive > High-voltage system > De-energize the high-voltage system: Read out prevention reasons
If it is not clear whether the vehicle has been de-energized, technical support must be contacted. Furthermore, the vehicle must be made inaccessible and blocked off with high-voltage barrier tape.
Measure
- After it has been determined that the vehicle is de-energized, the vehicle must be labeled as such with a corresponding sign.
Notes on identification of the high-voltage system
Remove right luggage compartment trim panel
- Remove the cover (1) to the top.
- Remove the cover (2) to the inside.
- Remove the luggage compartment trim panel (1) to the top.
Disconnecting the negative battery cable (starter unit battery)
Damage to battery terminal, the safety battery terminal or the intelligent battery sensor (IBS).
Damaged battery terminals can lead to malfunctions or vehicle electrical system faults.
- Detach battery terminal from battery pole by carefully shifting to and fro. Do not pry off using a tool.
- Slacken the nut (1) on the negative battery terminal.
- Detach the negative battery terminal (2) from the negative battery terminal.
- Put the battery ground lead to one side and secure it.
Remove the rear luggage compartment floor covering
- Open the luggage compartment floor covering.
- Press the lever (1) on the left and right inward in the direction of the arrow and detach it from the guide.
- Unclip the luggage compartment floor covering (1) from the clamps (2) in the direction of the arrow toward the top.
Removing the storage tray
- Loosen the expanding rivet (1).
- Remove the storage tray (2).
Disconnecting the negative battery cable of the system battery
Precondition
Ignition is switched off.
Risk of short circuits! Risk of fire!
- Make sure that there is no battery charger connected to the jump start terminal in the engine compartment.
- For vehicles with additional electrical systems (48 V electrical system, high-voltage vehicle electrical system), this absolutely must be deactivated before the vehicle battery is disconnected.
Damage to battery terminal, the safety battery terminal or the intelligent battery sensor (IBS).
Damaged battery terminals can lead to malfunctions or vehicle electrical system faults.
- Detach battery terminal from battery pole by carefully shifting to and fro. Do not pry off using a tool.
- Slacken nut (1).
- Detach the negative battery terminal including the intelligent battery sensor (2) from the negative battery terminal.
- Put the battery ground lead to one side and secure it.
Disconnect the battery earth lead for the active steering
Disconnect and connect the battery at the battery terminals only. Do not disconnect at the connectors!
- Loosen screws (1).
- Remove the retainers (2).
- Remove the separator (3) upward and set aside.
- Remove the foam insert (1) of the separator upward.
- Slide the auxiliary battery (2) to the right with the associated foam insert.
- Build date after 07/2016:
If necessary, release clips (1) and remove the cover (2).
The cover (2) is an optional installation.
- Open the protective cap (1).
- Release the screw at the battery negative lead (2).
- Put the battery negative lead (2) to one side and secure it.
- See DISCONNECTING AND CONNECTING BATTERY GROUND LEAD (ALL NEGATIVE BATTERY CABLES) (740I 2016-2022, 740I XDRIVE 2017-2022, 750I 2016-2019, 750I XDRIVE 2016-2022, M760I XDRIVE 2017-2022) , or DISCONNECTING AND CONNECTING BATTERY GROUND LEAD (ALL NEGATIVE BATTERY CABLES) (740E XDRIVE PHEV 2017-2019, 745E XDRIVE PHEV 2020-2022) .