This article discusses a common topic on the VWVortex forums: VCDS coding for a 2016 Jetta to enable cruise control. A user is attempting to retrofit a multifunction steering wheel (MFSW) with cruise control functionality onto their 2.0L MK6 Jetta. While other MFSW functions work correctly, the cruise control buttons trigger the horn. The following explores the user’s troubleshooting steps and provides context for those seeking similar modifications.
Understanding the Challenge of VCDS Coding for Cruise Control
Retrofitting cruise control often requires both hardware and software modifications. The user has already installed the MFSW and completed some wiring based on the seller’s guidance. The issue lies in enabling the cruise control functionality through VCDS coding. The user reports attempting to modify Bit 7 and Bit 2 in Byte 17 of the relevant control module. Unchecking Bit 7 results in an “implausible signal from BCM” error code, while checking it clears the code but doesn’t activate cruise control.
Exploring Potential Solutions within VCDS
The “implausible signal from BCM” error suggests a communication problem between the steering wheel control module and the Body Control Module (BCM). This could indicate incorrect wiring, a faulty BCM, or incompatibility between the MFSW and the car’s system. Forum users suggested unchecking Bit 7 and checking Bit 2 in Byte 17, a common coding modification for enabling cruise control. However, this didn’t resolve the issue in this case. Further investigation into the specific coding for the user’s Jetta model and the installed MFSW is necessary.
Delving into Wiring and Connections
Beyond coding, correct wiring is crucial. The user mentions connecting the steering wheel via LINBUS on connector T73b/17 and attempting to run a wire from the BCM (T73b/45) to the ECU (T94/65), as advised by other forum members.
Verifying the accuracy of these connections is paramount. Consulting wiring diagrams specific to the 2016 Jetta and the donor MFSW is essential. A common mistake is using incorrect pin assignments or failing to properly ground connections.
Utilizing the Full VCDS Autoscan for Diagnostics
The user provided a complete VCDS autoscan of their vehicle. This data is valuable for identifying potential issues beyond the initial coding problem. Analyzing the scan for any fault codes in the BCM, engine control unit (ECU), or steering wheel module can provide further clues.
Conclusion: Next Steps for Troubleshooting
Successfully retrofitting cruise control on a 2016 Jetta using VCDS requires a methodical approach. The user should focus on verifying the wiring based on reliable diagrams, double-checking the coding modifications against documented procedures for their specific vehicle and MFSW, and thoroughly analyzing the VCDS autoscan for additional clues. Consulting the VWVortex forums for support specific to their car and installed hardware is highly recommended. Careful attention to detail and a systematic troubleshooting process are key to achieving a successful outcome.
