Disconnecting the negative battery cable

WARNING: High-voltage system.
The high-voltage system operates on the basis of hazardous, electrical voltage and high currents. Mortal hazard through electric shock!

All work on the high-voltage system may only be carried out by specially trained and technically experienced personnel.
For additional information see:

SAFETY INSTRUCTIONS ON HANDLING HYBRID CARS

For additional information see:

NOTES ON REPAIR OF HIGH-VOLTAGE BATTERY UNIT

NOTE: TECHNICAL INFORMATION
With the ignition off and the high-voltage safety plug disconnected, the Check Control message "High voltage system faulty" is displayed by default.
The message "High-voltage system switched off" (absence of voltage) is only displayed when the ignition is switched on.

Preliminary work

Refer to REMOVING THE FLAP IN THE RIGHT-HAND LUGGAGE COMPARTMENT TRIM PANEL .
Refer to DE-ENERGIZE THE HIGH-VOLTAGE SYSTEM .
Refer to CHECK THAT NO VOLTAGE IS APPLIED .

Prerequisite

Ignition is switched off.

NOTE: TECHNICAL INFORMATION
For additional information see:
SAFETY INSTRUCTIONS FOR HANDLING VEHICLE BATTERY ,
NOTES FOR DISCONNECTING AND CONNECTING THE VEHICLE BATTERY
and NOTES ON INTELLIGENT BATTERY SENSOR (IBS)

NOTE: RISK OF DAMAGE
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.

Courtesy of BMW OF NORTH AMERICA, INC.

Slacken nut (1).
Pull off the negative battery cable including intelligent battery sensor (IBS) (2) upwards, put to one side and secure the components.