Replacing the body control module (BCM), often referred to as the hex09 module in VCDS, in an MQB platform Volkswagen Audi Group (VAG) vehicle like a Golf Mk7 requires careful consideration of component protection and coding. This article outlines the general process and potential challenges involved in this procedure.
Component Protection and Initial Steps
The first hurdle when replacing a hex09 module is Component Protection (CP), a security feature in MQB cars. After installing a new BCM, CP errors will likely be triggered in both the hex09 module and the gateway module (hex19). These errors prevent the new module from functioning correctly and must be cleared by a VW dealer or authorized agent using official tools.
Coding the New VCDS Body Control Module
Once CP is addressed, the next crucial step is coding the replacement hex09 module. This involves matching the coding of the new module to the old one. Critically, a complete backup of the original module’s coding is essential before removal.
MQB platform vehicles introduced a significant change to the hex09 module’s coding structure around mid-2016. VAG transitioned from long coding to an adaptation channel database. This impacts the coding process:
- Pre-2016 Modules: Long coding strings are used. Comparing and aligning these between the old and new modules is relatively straightforward, involving matching individual software switches.
- Post-2016 Modules: Adaptation channels replace long coding. This requires meticulous comparison of potentially thousands of individual channel settings. Tools like Microsoft Excel or Access can be invaluable for this task after converting the data into a flat file format (e.g., .CSV).
Data Parsing and Comparison Tools
“Data parsing” is the process of converting the adaptation channel data into a usable flat file format. VCDS offers a convenient backup feature called “ADMAP,” which can produce .CSV files. For other diagnostic tools like OBD11, third-party applications may be necessary to flatten the data structure for comparison. This streamlined format enables efficient digital comparison of individual channel settings between the old and new modules.
Challenges with Different Part Numbers
If the replacement hex09 module has a different part or software number compared to the original, complete coding alignment may be impossible. This is because different modules may have:
- Deleted Channels: Channels present in the old module but absent in the new one.
- New Channels: Channels present in the new module but not in the old one.
In these cases, informed guesswork and careful consideration of the vehicle’s features and modifications (e.g., headlight upgrades) are necessary to configure the new module correctly.
Conclusion
Replacing a Vcds Body Control Module (hex09) in an MQB platform vehicle is a complex process. Component Protection necessitates dealer intervention, while coding requires meticulous attention to detail and the use of appropriate tools for data comparison. Understanding the differences in coding structure between pre- and post-2016 modules is crucial. Finally, be prepared for potential challenges when working with modules that have different part numbers.
