This guide delves into the intricate world of Volkswagen’s lighting system, specifically focusing on enabling “pace lights” or the “urban joke” using a VCDS cable on the Virtus model. This modification allows the taillights to pulse with the turn signals, adding a unique visual flair. This process requires a deep understanding of the car’s Body Control Module (BCM) and its adaptation channels.
Understanding the VW Virtus BCM and Lighting Control
The Virtus, built on the MQB platform, relies heavily on its Body Control Module (BCM) for various functions, including lighting. The BCM manages a staggering number of adaptation channels, with a significant portion dedicated to exterior lighting. Each light boasts 19 dedicated channels, grouped to define parameters like bulb type, error reporting, and dimming behavior. These parameters are key to enabling the pace light functionality.
Decoding the Adaptation Channels
Each light’s 19 adaptation channels are categorized into specific groups:
- Type_Of_Load: Specifies the bulb type (incandescent, LED, etc.).
- Fehlerort_mittleres_Byte_DTC-DFCC_23: Defines the byte position in the configuration for error reporting.
- Lampendefektbit_Position: Pinpoints the bit position within the byte for error reporting.
The remaining 16 channels are divided into four subsets (AB, CD, EF, GH), each containing:
- Dimming: Controls the brightness level (0 for off, 127 for maximum brightness with LEDs).
- Dimming_Direction: Further refines dimming behavior (Minimize or Maximize).
- Light_Function: Dictates the light’s action, offering various possibilities, including blinking in sync or out of sync with the turn signal.
Enabling Pace Lights: Targeted Channels
To achieve the pace light effect, specific channels need adjustments. Remember, “Links” is German for Left, and “Recht” is Right. Modifying the wrong side will lead to undesired results. Focus on these channels:
- Leuchte23SL HLC7: Left outer taillight.
- Leuchte24SL HRA69: Right outer taillight.
- Leuchte33AMBL 3C72: Right inner taillight (boot lid section).
- Leuchte34AMBL 4C71: Left inner taillight (boot lid section).
Optionally, you can also modify the brake lights to flash:
- Leuchte20BR LA70: Rear left brake light.
- Leuchte21BR RC8: Rear right brake light.
Implementing the VCDS Adaptations
Within the identified channels, adjust these parameters:
- Dimming_CD: Set to 127 for full brightness or a lower value for a dimmer effect.
- Light_Function_C: Choose Blinken_rechts_Hellphase (right) or Blinken_links_Hellphase (left) for synchronized blinking with the turn signal. For out-of-sync blinking, use Blinken_rechts_Dunkelphase (right) or Blinken_links_Dunkelphase (left).
- Dimming_Direction_CD: Set to Maximize.
Important Considerations and Limitations
- Rear DRL Deactivation: Disable rear Daytime Running Lights for this modification to work.
- Headlight Dependency: Pace lights function only when headlights are off. With headlights on, taillights revert to default behavior.
- Brake Light Functionality: Brake light flashing works even with headlights on. Pressing the brake pedal while the turn signal is active will override the flashing, making the brake light illuminate steadily.
Proceed with Caution
This modification should be undertaken with caution and at your own risk. Improper adjustments could lead to malfunctions. Always back up your original settings before making changes. Consult with experienced VCDS users if you have any doubts.
This guide offers a starting point for enabling pace lights on the VW Virtus. Further experimentation and research might unlock additional customization possibilities within the complex BCM system. A deeper understanding of the “Light_Function” parameter, in particular, could reveal further lighting effects.
