Upgrading the Symphony radio in your Audi B7 S4 to an RNS-E navigation system (8P0 035 193 G) opens up a world of possibilities. While features like navigation and media playback usually work seamlessly, activating Bluetooth can be tricky. This guide focuses on using VCDS to enable Bluetooth connectivity in your B7 after an RNS-E upgrade, specifically targeting the Bluetooth module (8P0 862 335 J).
Troubleshooting Bluetooth Connectivity with VCDS
After installing the RNS-E, you might find that your phone doesn’t connect. Using VCDS (version 17.1.3 or newer), a diagnostic scan reveals the presence of the Bluetooth module (device 77) without any error codes. However, a full auto-scan might show missing devices:
- 37 – Navigation
- 56 – Radio
- 77 – Telephone
While devices 37 and 56 aren’t directly addressable, device 77 (telephone) responds and reports no errors, indicating a potential communication issue.
The RNS-E primarily communicates via the K-line protocol. A common misconception is that simply connecting the existing wiring harness to the new unit will enable all functionalities. While this often works for basic features, Bluetooth activation requires further configuration.
Understanding K-Line and CAN Bus Communication
The key to enabling Bluetooth lies in understanding the communication protocols involved. The original Symphony system and the Bluetooth module likely communicate using the K-line. However, the RNS-E might require communication via the CAN bus. Within VCDS, the coding for the Bluetooth module (0xxx?xx) allows switching between these protocols:
- 6: K-Line communication
- 4: CAN Bus communication
Changing the coding from 6 to 4 might initially seem like the solution. However, this often results in a communication error, forcing a revert back to the original K-line setting (coding 6).
Potential Solutions and Further Investigation
This suggests a potential incompatibility or missing link in the communication chain. Possible solutions include:
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Verifying Wiring: Double-check the wiring harness connections to ensure all pins are correctly seated and undamaged. Consult wiring diagrams specific to your B7 S4 and RNS-E model to identify any potential discrepancies. A pin swap within the connector might be necessary, but proceed with caution and consult reliable sources before attempting any modifications.
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Updating Firmware: Ensure your RNS-E and Bluetooth module have the latest firmware updates. Outdated firmware can lead to compatibility issues.
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Consulting Forums: Research online forums dedicated to Audi and VCDS. Other users might have encountered similar issues and found successful solutions. Search for threads related to “B7 Bluetooth activation,” “RNS-E Bluetooth retrofit,” or “VCDS Bluetooth coding.”
Conclusion: Enabling Bluetooth in Your B7
Enabling Bluetooth after an RNS-E upgrade in a B7 S4 requires a deeper understanding of communication protocols and potentially some wiring adjustments. While VCDS confirms the presence of the Bluetooth module, the communication gap between the module and the new head unit needs to be bridged. By carefully investigating wiring, firmware updates, and seeking advice from experienced users, you can successfully enable Bluetooth and enjoy hands-free communication in your Audi B7 S4.
