Redundant Data Storage
WARNING: This page is about a different car, the 2005 BMW 645Ci and 2004 BMW 645Ci. However, it is still accessible from the selected car via links, so may be relevant.
If the instrument cluster is exchanged, the stored data (e.g. total distance reading) must be retained. This will make it possible to detect any evidence of manipulation.
In order to guard against manipulation, the following data are stored redundantly (second copy) in the CAS control unit:
- Vehicle identification number
- Total distance reading (kilometer reading)
- Data related to the scopes of the Condition Based Service
The data is verified each time terminal 15 is switched on. A manipulation dot is shown in the LCD display in the event of any discrepancy. The manipulation dot appears to the left of the trip distance recorder.
The manipulation dot is displayed in the following cases:
- The vehicle identification number stored in the instrument cluster is different to the one stored in the CAS control unit.
- A vehicle identification number is not stored in one of the two control units (e.g. new component).
- The module in the instrument cluster for storing the total distance reading is faulty (the kilometer reading is shown as 999999).