Retrofitting a newer head unit into an older vehicle can unlock modern features like Bluetooth connectivity. This guide explores the challenges and solutions encountered when installing an RNS315 unit, specifically focusing on activating Bluetooth using VCDS (Vag-Com Diagnostic System) in a 2008 Volkswagen GTI.
Understanding the Challenge: RNS315 Retrofit and Bluetooth Activation
The owner of a 2008 GTI with a factory red display and an older CAN gateway (ending in 530K) installed an RNS315 unit from a 2015 Jetta. While the RNS315 supports Bluetooth, enabling it in the GTI required more than a simple plug-and-play installation. Initial attempts to enable Navigation in VCDS were successful, but the system couldn’t detect the radio, preventing Bluetooth functionality. Although the radio functioned without Bluetooth and steering wheel controls, a known incompatibility between older CAN gateways and the RNS315 prompted a gateway upgrade.
The Solution: CAN Gateway Upgrade and VCDS Coding
A newer CAN gateway (7N0907530AJ, 2014 build) was installed, and the coding was meticulously transferred from the old gateway to the new one. This resolved the radio detection issue within the Navigation menu in VCDS. The critical step to activate Bluetooth involves modifying the coding in the Navigation module. Specifically, unchecking byte 3 bit 5, which corresponds to “Telephone Transceiver/Bluetooth (internal) inactive,” is required. However, attempting this change resulted in a persistent “Error 31: Request out of range – coding rejected” message.
A Bluetooth microphone was also wired and connected to the RNS315, ensuring the hardware was in place. Despite these efforts, achieving Bluetooth functionality remained elusive due to the coding error. Further investigation is needed to understand why the coding change is being rejected. Possible causes include incorrect coding in other modules, incompatibility between the RNS315 and the GTI’s software version, or a need for specific adaptations within VCDS.
Troubleshooting and Next Steps
The full VCDS scan revealed fault codes in the new CAN gateway (01044 – Control Module Incorrectly Coded) and the Navigation unit (1048641 – Control Module Incorrectly Coded), confirming the coding issue. Addressing these fault codes is crucial for enabling Bluetooth. Further troubleshooting steps include:
- Verifying Coding Compatibility: Consulting online resources and forums specific to VW/Audi coding can provide insights into the correct coding parameters for the specific RNS315 and GTI combination.
- Checking Long Coding: Examining the long coding within both the CAN gateway and Navigation module may reveal discrepancies or incorrect settings that prevent Bluetooth activation.
- Performing Component Protection Removal: If the RNS315 was taken from a donor vehicle, component protection may need to be removed using specialized tools or software to allow it to function correctly in the GTI.
Successfully enabling Bluetooth often requires a deep understanding of VCDS and the intricacies of VW/Audi electronics. This case highlights the complexities involved in retrofitting newer components into older vehicles and the importance of accurate coding for proper functionality. While the initial steps were taken correctly, resolving the “Error 31” message and the fault codes is crucial for achieving Bluetooth connectivity in this GTI. This requires further investigation into coding compatibility and potential component protection issues.
Conclusion
Enabling Bluetooth on a retrofitted RNS315 can be a challenging but rewarding process. By understanding the potential coding conflicts and utilizing VCDS effectively, it’s possible to unlock the desired functionality. This case study demonstrates the importance of thorough research, careful coding, and persistent troubleshooting when integrating newer technology into older vehicles. A correct diagnosis of the “Error 31” message and addressing the fault codes in the CAN gateway and Navigation module are the next steps toward achieving seamless Bluetooth integration in this 2008 GTI.
