@bmwtvboy You could try switching banks on the post cat sensors, they are under the top engine cover and easy to get to, don't make a neat job of it because you'll be changing em back. If light goes out after a while you probably have depleted cats. The cat cleaner in a can can work but only lasted a short time for me.

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1988 325is (purchased new) sold
2004 X5 3.0 2005 X3 2.5
2008 X5 3.0 (new to me)