Whenever the airbags in a VW or Audi have deployed, crash data is stored in the airbag controller and cannot be cleared. In order to restore the car to proper operation, the airbag controller must be replaced. This Ross-Tech-Tip will describe the procedure for coding a brand new airbag controller in many recent VW vehicles. (Most Audi models use different procedures.) As with all diagnostics and repair procedures, you should consult a Factory Repair Manual for the vehicle being serviced.
A word of caution: The controllers in VW/Audi cars have an
electro-mechanical switch that deploys the airbags, somewhat like
the hammer and trigger on a gun. This switch cannot be “re-cocked” and you should stay far away from any who claim to be able to “reset” (re-cock) a used airbag controller. The liability of pre-mature deployment or the failure to deploy would result in severe consequences to your business.
Step 1: Find and resolve problems with the airbags or the airbag igniters prior to installing a new controller.
Step 2: Install the new controller.
Step 3: Code the module.
New airbag controllers from the factory often contain a Soft Coding of all zeros and must be coded once they have been installed in the vehicle. The factory scan tools use “Guided Fault Finding” to assist technicians in the coding of these controllers but most aftermarket scan tools do not provide such assistance. VCDS, while not using “Guided Fault Finding”, can offer a suggested coding for the module under test as shown in Figure 1.This is a best guess suggestion and may not be the correct coding. If it is not correct, the controller should simply refuse to accept it and the coding will remain at 00000.
Accept the suggestion from VCDS and enter the value in the “Software Coding” box. Click “Do It”.