12 42 500 Replacing Battery Positive Lead (Between Starter, Alternator and Battery Positive Terminal)

Necessary preliminary tasks: 

• Read out fault memory of DME control unit
• Switch off ignition
• Disconnect battery negative lead (See 61 20 900 DISCONNECTING AND CONNECTING BATTERY NEGATIVE LEAD and/or 61 20 900 DISCONNECTING AND CONNECTING BATTERY NEGATIVE LEAD )

  Follow instructions for disconnecting and connecting battery (See 12 00 ... INSTRUCTIONS FOR DISCONNECTING AND CONNECTING BATTERY and/or 12 00 ... INSTRUCTIONS FOR DISCONNECTING AND CONNECTING BATTERY )

• Remove intake air manifold

Remove protective cap (not shown).

Release screw, remove battery positive lead (1) from battery positive terminal.

Tightening torque 12 42 3AZ, see ENGINE ELECTRICAL SYSTEM -- TORQUE SPECIFICATIONS -- TWIN TURBO .

Fig 1: Locating Battery Positive Lead From Battery Positive Terminal

Courtesy of BMW OF NORTH AMERICA, INC.

Remove protective cap and release nut underneath.

Tightening torque 12 42 1AZ, see ENGINE ELECTRICAL SYSTEM -- TORQUE SPECIFICATIONS -- TWIN TURBO .

Disconnect battery positive lead (1) from alternator.

Fig 2: Locating Battery Positive Lead From Alternator

Courtesy of BMW OF NORTH AMERICA, INC.

Unlock plug (1) and remove.

Unfasten nut.

Tightening torque 12 42 2AZ, see ENGINE ELECTRICAL SYSTEM -- TORQUE SPECIFICATIONS -- TWIN TURBO .

Disconnect battery positive lead (2) from starter motor.

Fig 3: Locating Starter Motor Nut

Courtesy of BMW OF NORTH AMERICA, INC.

Unclip battery positive lead (1) from holder (2) and remove.

Fig 4: Identifying Battery Positive Lead & Holder

Courtesy of BMW OF NORTH AMERICA, INC.