On older M57 DDE 4 models there is a code if EGR is disabled but it doesn't cause anything else, hence no mapping needed in those. M57N with DDE 5/6 will need it mapped out. Mainly MAF shows the discrepancy of too much fresh air compared to the load situation telling that there is no EGR flow.

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E39 530dA -02 M-Sport Messing metallic
E53 X5 3.0dA -06 Sport Stratus grey
E70 X5 40d -12 M-Sport Space grey