Battery: Service Precautions

61 12 ... General Information On Intelligent Battery Sensor (IBS)

Notice: 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 trickle charger connected at the 12 V charging socket will be disconnected from the battery. Only charge the battery via the jump start terminal point. 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 ground 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 pole shoe from the battery terminal:
- Do not pull on the ground cable.
- Do not place any tools under the IBS to lever off the pole shoe.
- 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 as standard when replacing the battery.
- Register battery replacement via Service functions in diagnosis system.
- Delete fault 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 replace the IBS when there is a corresponding fault entry in the DME or DDE.