Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
MMI Infotainment System Through May 2009
The data for the infotainment, telephone, navigation, voice control system, audio players, sound system and data bus on board diagnostic interface -J533- is transmitted via the fiber optic MOST BUS.
The connection to the other BUS systems in the vehicle are performed by the data bus on board diagnostic interface.
The central control module is the front information display control head control module -J523-. The transfer of signals representing the instrument cluster display occurs via the MOST-Bus to data bus on board diagnostic interface and from there via CAN-Bus (instrument cluster) to the instrument cluster.
Fault finding is performed via guided fault finding using vehicle diagnosis, testing & info. system VAS5051B.
Additional information, refer to self study 286, New data bus systems - LIN, MOST Bluetooth.
MMI Infotainment system
- Front information display control head control module behind glove compartment
- Multimedia control head -E380- in lower center console
- Front information display control head -J685- in center instrument panel
- Radio -R- (with speech input control module -J507-) located in luggage compartment (left rear)
- Satellite Radio -R146- in left rear of luggage compartment
- Digital sound system control module -J525- in the luggage compartment (left rear)
- Sound systems: Standard/BOSE
- Media player in position 1 -R118- with CD changer -R41- /external audio source connection -R199- inside the glove compartment on the left side
- Media player, position 2 -R119- with CD changer in right of glove compartment
- Navigation system with CD drive control module -J401- in luggage compartment, left rear
- Mobile phone prep
- Multifunction steering wheel
Notes on MOST Bus
In addition to the CAN bus systems, the optical data bus system MOST bus is used.
A fiber optic cable is utilized as the connecting cable. Fiber optic cables are routed inside corrugated tubes for protection.
Replace complete fiber optic cable if possible.
Make sure that the face surfaces of the connectors do not become soiled.
If the connectors are disconnected: Attach protective cap for cable connector VAS 6223/9.
Observe the minimum bending radius of 25 mm when routing fiber optic cables. Fiber optic cables must not be pinched or bent.
Repairing fiber optic cables. Refer to FIBER OPTIC CABLE .
Additional information, refer to self study 286, New data bus systems - LIN, MOST Bluetooth.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.