Steering Mounted Controls Assembly: Description and Operation

Multifunction Steering Wheel

Description

Buttons are integrated in the steering wheel for easier operation of the radio (R), cellular telephone (R54), navigation and CD changer (R41).

With Tiptronic (automatic transmission), additional switches are installed.

The electronics integrated in the steering wheel take over signal processing from the buttons and transfer signals via the LIN data bus (single wire bus) to the steering column electronics control module (J527). The conversion to CAN BUS (comfort) takes place there.

The multi-function steering wheel is part of the complete steering column switch module (SMLS) system and delivers data via the LIN data bus to the steering column electronics control module.

The individual button blocks and the Tiptronic switch can be replaced separately.

The electronics inside the steering wheel cannot be replaced individually. If faulty, the entire steering wheel must be replaced.

Fault finding is performed via "Guided Fault Finding" using the Vehicle Diagnosis, Testing & Information System (VAS5051).