Notes on intelligent battery sensor (IBS) (M3 base, M3 Competition, M3 Competition M xDrive, M3 CS)

Note! Do not connect the charger to the 12 V charging socket 

The 12 V charging socket is supplied with voltage by the rear power distribution box via relay. This relay drops out after terminal 15 OFF

This means that a battery maintainer connected at the 12 V charging socket will be disconnected from the battery. Only charge the battery via the jump start terminal. Only then can the voltage supply be registered by the vehicle

Warning! Danger of destruction in event of mechanical strain 

• Do not introduce any additional connections at the battery negative terminal
• Do not modify the grounding cable. The ground cable also serves heat dissipation
• Do not establish any connection between the IBS and the sensor screw
• Do not use force when disconnecting the terminal cover from the battery terminal: 
  • Do not pull on the ground cable
  • Do not place any tools under the IBS to lever off the terminal cover
• Do not use IBS connections as levers
• Use a torque wrench and set tightening torque in accordance with repair instructions
• Do not release or tighten down sensor screw (Torx screw)
• Avoid contact between IBS and ground

Warning! Danger of destruction to IBS and wiring upon battery replacement 

• The IBS and wiring can be destroyed by mechanical strain upon battery replacement. Therefore avoid mechanical strain
• The size (capacity) of the battery required for the car is coded in the Car Access System (CAS)
• Use the battery size (capacity) installed standard upon battery replacement
• Recode the Car Access System (CAS) when installing a battery with a different capacity
• Register battery replacement via service functions in diagnostic system
• Delete fault code entries in the Digital Engine Electronics (DME) associated with battery replacement
• Always proceed in accordance with the repair instructions
  NOTE: Battery draining possible in spite of the intelligent battery sensor IBS being fault-free
• A battery can be drained (e.g. with lights or radio switched on) even when the IBS functions perfectly in conjunction with power management
• For this reason, only exchange the IBS when there is a corresponding fault code entry!