Requiring all 4 tires be replaced at the same time is outlandish on a vehicle that has a factory staggered setup. The rears will almost always need to be replaced before the front because of the inner and center tread wear. But maybe I'm just getting too excited about such a requirement. My E30 iX has perfectly even wear front and rear, but it also has a square tire setup.
Isn't the SAS test, just verifying the angle is read correctly while turning left and then turning right? Yes, SAS would cause DSC to failsafe which will make the ABS light also come on.
4x4 light should stay off, except for that transfer case issue with the gear.

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Olympic Peninsula, WA, USA
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2005 Mini Cooper 100k, British Racing Green/Silver-Black
04/2002 4.6is 140k, Silver/Black-Alcantara *FOR SALE*
1989 325iX 270k, Diamond Black/Black
1984 318i 370k *SOLD* (First Bimmer)
Honorable Mentions: '71 2002, '87 325, '90 325ic, '92 525it, '93 325i, '94 530i