Brief description of components

The SMG system comprises the following key components:

• 4 wheel-speed sensors 

  The wheel-speed sensors of the Dynamic Stability Control (DSC) measure the wheel speeds of the individual wheels.

• RPA button 

  > E46, E53, E83, E85, E86

  The RPA button is only needed for initializing the PRA.

  (RPA initialization means "teaching the system the tire pressures").

• CID: Central Information Display 

  Vehicles that are equipped with CID are initialized using the CID.

• On-board computer button and rocker switch on turn-signal/main-beam switch 

  > E87, E90, E91, E92, E93, R56

  Initialization is performed on the LCD display, using the BC button and the rocker switch on the turn-signal/main beam switch. The on-board computer functions are selected with the rocker switch.

  The R56 does not have a rocker switch. The on-board computer functions are selected with the BC button.

  The RPA software is in the following control units, depending on model series:

• RPA control unit 

> E46 all-wheel drive

The E46 All-wheel drive has a separate RPA control unit.

The 4 wheel-speed sensors measure the wheel speeds. The DSC control unit sends the signals through 4 direct wires to the RPA control unit.