Trailer Hitch Retrofitting (4L)

These instructions may not cover mechanical/electronic details, they will only list the the diagnostic side (coding etc.). Additional details for the mechanical/electronic work needed are part of the retrofitting instructions provided by the parts supplier (i.e. trailer hitch retrofits) or can be found in the factory repair manuals and wiring diagrams.

Installation & Wiring

Information regarding the Installation can be found in the Repair Manuals, the Wiring Diagrams, the Parts Catalog and/or the Instructions included in the Retrofitting Kit.

Configuration

The following Activations are necessary to ensure that the newly fitted parts are properly recognized and are ready to use.

Make sure to enter a Plausible WorkShopCode (WSC) like 12345-123-12345 on the Coding Screen. Control modules with WSC 00000-000-00000 stored can result in rejected coding or a 01042 - Control Module Not Coded Fault Code that will only clear if the WSC used for Coding the Module is NOT 00000-000-00000.

• Update the Installation List in the Gateway (J533 / #19).
  • Register the newly added 69 - Trailer Control Module via the Installation List Function.
• Update the Trailer Control Module (J345 / #69) Coding.
  • Not all Retrofitting Kits contain Diagnostic capable Trailer Control Modules, some Aftermarket Modules may even be pre-coded. This Step can be ignored for Modules which are not Diagnostic capable.
  • Due to different Control Modules and Equipment in the Car the actual Coding Table is not shown here but will automatically be used by the Long Coding Assistant once you access the Function using VCDS. If an Aftermarket Module is installed, check the Retrofitting Kit for further Instructions.
• Update the Engine Control Module (J623 / #01) Coding.
  • Make sure that the Engine is NOT running, otherwise the new Coding will be rejected. Models equipped with Start/Stop System do have a Shutoff Switch/Button which will deactivate the Start/Stop Function.
  • For Engines with a 2nd Engine Control Module (J624 / #11) this needs to be coded as well.
  • As a Rule of Thumb, If the Engine uses conventional Short Coding (Coding is 7-digits like 0011312) the Long Codding Assistant does NOT apply. Modules using Short Coding typically do NOT support or require Trailer Configuration Coding. If the Engine Control Module uses a Long Coding the Activation is done in (Long) Coding itself through via Coding Assist. Please also note that there are different Coding Variants for Long Coding.
  • Due to different Control Modules and Equipment in the Car the actual Coding Table is not shown here but will automatically be used by the Long Coding Assistant once you access the Function using VCDS.
• Update the Brake Electronics (J104 / #03) Configuration.
  • To enable the Trailer Stabilization Subtract 0000016 from the existing Coding (e.g. 0033937 - 0000016 = 0033921).
  • Additional Information may be shown once you access the Coding Function using VCDS.
• Update the Level Control (J197 / #34) Coding, if installed.
  • Due to different Control Modules and Equipment in the Car the actual Coding Table is not shown here but will automatically be shown once you access the Function using VCDS.
• Update the Parking Aid (J446 / #76) Coding, if installed.
  • Due to different Control Modules and Equipment in the Car the actual Coding Table is not shown here but will automatically be shown once you access the Function using VCDS.
• Update the Rear View Camera (J772 / #6C) Coding, if installed.
  • Due to different Control Modules and Equipment in the Car the actual Coding Table is not shown here but will automatically be displayed once you access the Coding Function using VCDS.
• Update the Lane Change Assist (J769 / #3C) Coding, if installed.
  • Due to different Control Modules and Equipment in the Car the actual Coding Table is not shown here but will automatically be displayed once you access the Coding Function using VCDS.
• Update the Distance Regulation (J428 / #13) Coding, if installed.
  • Due to different Control Modules and Equipment in the Car the actual Coding Table is not shown here but will automatically be displayed once you access the Coding Function using VCDS.

If you are having trouble finding/calculating the proper Coding using the Long Coding Assist please Register and post in our Retrofitting sub-forum. Make sure to include a complete Diagnostic Protocol (Auto-Scan) from the Car and state which steps/work you have performed.