Encoding the MK6 Golf rear lights
Here you will find useful information and handy tips relating to encoding LED rear combination lamps based on a Golf 6.
Important safety note
The number of different vehicle types is increasing from year to year. The success of “niche models” is further softening the delineation between traditional classifications such as station wagon, sedan, or van. In addition, new developments in the fields of driver assistance, communication, and safety systems are creating further distinctive features to fulfil customer wishes.
Modifications and tuning of the exterior lighting are in the Top 10 of customer wishes – particularly since the introduction of daytime running lights. Conversion to xenon headlights or LED rear combination lamps are also in demand.
However, the challenges involved in the installation of such lighting systems increase with the complexity of the products.
For some years now, control units have been controlling, regulating, and monitoring lighting functions. If different lamps or headlamps are installed in the vehicle, the control unit has to be “informed”. This is where “encoding” comes into the picture. During encoding, parameters are changed in the respective control unit to guarantee perfect operation of the lighting functions.
In addition to the HELLA rear combination lamps, adapter cables are always required since LED lamps have different connections. These adapter cables are relatively easy to make yourself.
The following items are required for complete conversion:
Cut the 6 cables in the middle so that you have 12 cables: One end with a crimp contact, the other without contact. Then shorten the cables to approx. 10 cm.
Click the cable ends equipped with the blade terminals into the connector (7N0 972 703) for the LED lamps.
Strip the other cable ends by approx. 6 mm and crimp contacts 8KW 863 931-003 in place. You will need a pair of pliers for non-insulated crimp contacts for this (HELLA no. 8PE 002 007-011).
During this working step, make sure that the LED connector with the red locking hoop is at the top and the crimp contacts are aligned evenly to one another. This prevents the cables twisting during subsequent connector assembly.
Click the cable ends with the blade terminals into the socket (191 972 713). Make sure the cables are in the right order! (Red locking hoop from connector and chamber numbers 1, 2, 3 from the socket must be visible from above).
Now repeat these working steps for the other three adapters
Open the trunk lid. Pull the side panel in the trunk backward and off so that the knurled-head screw is easy to reach.
Unlock the contact plug and remove it from the light.
Insert the adapter into the LED light (exterior light). Then push the red locking hoop to the limit stop toward the light.
Insert the LED light into the body and tighten using the knurled nut.
Caution! Heed the guides on the light during insertion.
Connect the adapter socket with the connector from the vehicle harness
Unlock and remove the flap from the trunk lid.
Caution! Unlatch the plastic strip on the side of the light and remove downward.
Insert the inner LED light into the body and tighten using the M8 screws. Click the plastic strip back onto the light.
Connect the adapter with the light and the vehicle harness.
Install all the removed parts in reverse order.
On account of the different characteristics of lamps with filament bulbs and lamps with LEDs, the control unit – known as “Body Control Module” (BCM) at VW – has to be “encoded”. Parameters are changed in the control unit in such a way that the LED rear combination lamps work perfectly. If this does not happen, fault messages will appear on the display and lamps will only have limited functionality. (The stop light in the tailgate can shine more brightly than the stop light in the exterior lamps).
Conversion is not possible with every BCM. There are different specifications for the Golf VI concerning the production date (vehicle) from which perfect functionality of the lighting functions is guaranteed. Before a vehicle is converted to LED lamps, we recommend reading out the BCM software version (see Figure 9).
Generally speaking, there are two different BCMs: The old one with software version 03XX. Proper conversion is not possible with this BCM. If a customer would still like to equip their vehicle with LED lamps, a new BCM will have to be installed as well. The old BCM cannot be updated to a newer software version.
Conversion is generally possible with the new BCM with the software version 05XX (0537, 0541). In vehicles with these software versions and standard xenon headlights, there is still a special factor that has to be taken into account: After the rear combination lamps have been encoded, the option “permanent driving light” (low beam is always activated when the engine is switched on) is no longer available. If this option is to remain active, the BCM must be updated to a newer version (SW version 0575 or later).
Once the software version has been checked, encoding takes place. For this purpose, the “long coding” is requested via the menu items Central electrics – Coding. For LED rear combination lamps, only byte 18 is changed. The BCM lists the possible changes for this byte in a sub-menu (see Figure 10).
In this case, the bit must be changed to “04”. Once encoding has been completed, faults will no longer be indicated.