Central Coding Key (ZCS): Notes
The Central Coding Key is a unique 37 digit code (originally 48) that contains all model and equipment information of the vehicle that is relevant to coding. The ZCS code for a particular vehicle is created by the factory, based on the individual equipment and country version of the vehicle. The encoding equipment at the factory duplicates the ZCS and encodes the installed control modules in the vehicle after assembly.
The ZCS code is stored in one or two modules (vehicle dependent). This code is retrieved by the coding software of the DISplus or MoDiC whenever coding of other control modules is necessary.
The coding process for modules that are encoded by the ZCS occurs by selecting or activating data maps already contained in the control module. The control modules have an EPROM that is pre-programmed with "resident data". There is more information (data) than is necessary to operate the control module. This data is ready to be activated as soon as the Key is made available to "unlock" the program. ZCS is called a key be cause it unlocks a specific set of instructions of a new control module or recodes a used control module.
Prior to coding a control module, the coding software checks whether the stored ZCS code, the coding data and the version of the control module agree. If these deviate from each other the coding program will determine a new "Central Code".
Use of the Central Coding Key began with the introduction of the E31 in 1990.
A ZCS codable control module may be coded an infinite number of times.