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.
Structure and inner electrical connection: Notes
The ASD control unit is connected to the CAN bus.
Example:
- I01, I12: Connection on K-CAN4
- F10: Connection on K-CAN2
- F56: Connection on K-CAN4
- G11, G12: Connection on K-CAN4
Observe the wiring diagram in the diagnosis!
The ASD control unit is supplied with terminal 30B.
The ASD control unit has one input RAD_ON and one output RAD_ON. The output can be switched independent of the input.
Essentially, the ASD control unit consists of the following elements:
- Microcontroller
(also controls the digital sound processor)
- Digital sound processor
(for continuous processing of digital signals via digital signal processing)
- Digital/analogue converter
(D/A converter for generation of the analogue ASD signals from the digital audio signals of the digital sound processor)
- Analogue summing device
(for addition of the analogue audio and ASD signals)
- Power stages
(for adjustment of the output of the analogue audio signals to the vehicle speakers)
- Transmit/receive system for CAN messages
The following graphic shows an example of the ASD control unit with bus connection on the K-CAN2.
| Item | Explanation |
|---|---|
| 1 | Active Sound Design (ASD) |
Pin assignments
The graphic above shows only the supply and bus connection. The current pin assignment is recorded on the wiring diagrams in the ISTA diagnosis system (Integrated Service Technical Application). Click on the component code in the wiring diagram to activate the "Installation location" and "Pin assignment" tabs.
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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.