Disconnect battery ground lead (engine compartment)

• Loosen the lock (1)  .
• Remove cover (2)  .

  Courtesy of BMW OF NORTH AMERICA, INC.

  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.
• Loosen the nut on the negative battery terminal (1)  .
• Detach the negative battery terminal (1)  from the negative battery terminal.
• Put the battery ground lead to one side and secure it.

Courtesy of BMW OF NORTH AMERICA, INC.