Understanding the coding for Revision C 55-Headlight Range Control modules can be challenging due to the lack of readily available documentation. Unlike later revisions that utilize long coding, these older modules rely on a decimal value representing underlying binary options. This article aims to shed light on these hidden settings and explore potential features like Motorway Light and City Light.
Deciphering the VCDS 55-Headlight Range Binary Code
While official documentation is scarce, experimentation and community knowledge have revealed some of the functionalities controlled by each bit in the coding decimal. Here’s a breakdown of current understanding:
Bit 0-3: Vehicle Model Identification (Uncertain)
Bit 4: Curve Light Activation (0 = Always Active, 1 = Personalized via Assistants Menu)
Bit 5: Unknown
Bit 6: Rain/Light Sensor (0 = Not Installed, 1 = Installed)
Bit 7: Unknown
Bit 8: Driving Side (0 = Left Hand Drive, 1 = Right Hand Drive)
Bit 9: Unknown
Bit 10: Number of Leveling Sensors (0 = 2 Sensors (Front & Rear), 1 = 1 Sensor (Rear Only))
Bit 11: Dynamic Chassis Control (0 = Not Installed, 1 = Installed)
Bit 12: Region (0 = Not NAR, 1 = NAR)
Bit 13-14: Unknown
Bit 15: All-Wheel Drive (0 = Not Installed, 1 = Installed)
Bit 16-21: Unknown (Potentially Extended Vehicle Model ID)(Image: Example of a VCDS scan showing the 55-Headlight Range Control module)
Unlocking Hidden Features: Motorway Light and City Light
Several undocumented bits may control features not explicitly mentioned in available resources. These include:
- Motorway Light: Extends the headlight beam at higher speeds (e.g., above 120 km/h).
- City Light: Shortens and widens the beam at lower speeds (e.g., below 60 km/h).
- High Beam Assist (HBA): Enables automatic high beam control via a camera.
- Startup Calibration Sequence: Controls the headlight movement during the self-test on startup.
- Cornering Light Disable: Potentially allows disabling the cornering light feature.
Determining the specific bits responsible for these functions requires further investigation and testing.
Challenges and Considerations with VCDS 55 Coding
One challenge encountered when working with Revision C modules is the unexpected activation of static cornering lights in Daytime Running Light (DRL) mode or when using comfort turn signals. This might be linked to incorrectly setting bit 6 (Rain/Light Sensor) to 1 when a sensor isn’t present, causing the module to assume it’s always dark.
(Image: Headlight with active cornering light)
Conclusion: Seeking Clarity on VCDS 55 Headlight Range Coding
This article highlights the complexities of coding Revision C 55-Headlight Range Control modules. While some bit assignments are known, many remain a mystery, especially those related to potentially desirable features like Motorway Light and City Light. Further research and community collaboration are essential to fully decode these modules and unlock their hidden potential. Sharing information about undocumented bit assignments with Ross-Tech could potentially lead to updated label files and improved VCDS functionality for these older modules.
