Quote:
Originally Posted by X5chemist
Doesn't the X-drive do an auto adjust every time it's started? I thought I read it here.
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It does re-calibration at shutdown. Not sure if it does anything at start-up - the TIS says nothing about that: -
Calibration sequence:
When terminal 15 is OFF, a calibration sequence is performed. During this calibration sequence, a certain angle setting of the VTG actuator motor has a corresponding locking torque assigned. The effects of wear are also taken into account when this is done.
The multi-plate clutch is closed fully and separated once during this calibration sequence. When this happens, the current draw is measured at the respective angle setting of the VTG actuator motor. This determines the beginning and end of the closing movement for the multi-plate clutch. The angle setting is recorded by means of the integral incremental sensor in the VTG actuator motor. These values are stored and are used as data when the car restarts.
The Oil Wear Adaptation that should be done in an xDrive ATC-500 when completing a fluid (power divider oil) change is to reset the oil wear and clutch friction adaptations. The clutch friction co-efficient changes with fresh oil so the system needs to be re-adapted to allow for this.
Makes a BIG difference!! Hence this thread.
