Notes On SCN Coding Of Control Units - Ah54.21-P-0004-01X

Model 907 

The Software Calibration Number (SCN) is specified by law in Europe and the USA for all control units relevant to exhaust emissions as of model year 2002.

Accordingly the software and coding of such a control unit must be clearly identifiable by means of the SCN. As a number the SCN consists of 16 numbers. The first 10 places correspond to the object number to be coded (normally the object number of the control unit software). The next 2 places designate the manufacturing plant or field organization where the vehicle was coded. The last 4 places together form a count number for the variants of the coding string of the vehicle-specific as-built configuration. This count number increases consecutively for each newly formed variant.

If special equipment has been installed or removed in the vehicle (e.g. retrofitting a telephone), these retrofit codes must be added to the central system before requesting the SCN coding data. The appropriate national organization must be contacted (MPC) for this.