The 6 coils don't control the valve timing, they supply the spark to
each of the 6 sparkplugs to fire the cylinders.

Is it the same exact coil that has failed?  Perhaps the one installed as
a replacement was of poor quality?  If so, that's just bad luck.  If it
is a different cylinder that has failed I would be somewhat concerned
that the coils were somehow stressed by some over-voltage condition or
other earlier failure.

BTW - do not drive the car with a bad coil (even if you can get it to
run OK above 2000 rpm) or you are likely to destroy the expensive
catalytic convertor by dumping the raw fuel from the bad cylinder into it.

-Fred W

This is actually a common problem for many car manufacturers. VW had
terrible problems with coils a few years ago, particularly in their 1.8T
engine. Virtually no supply of new coils, so dealers had to raid their
new car inventories for coils to put in customers' cars. A friend's
Infiniti has had all 6 coils replaced under warranty. Another friend had
all 4 coils in his Renault replaced under warranty.

When, and at what mileage, did you have the coil(s) replaced the last
time? You could ask the dealership to do the repairs for free, sometimes
they will do that as a good will gesture when there are special
circumstances (like repeat failures or known weak points).

I have a 2003 530i and just had one fail at 17,000 miles.  The coils
were on back order until BMW would release new (revised?) coils to the
pipeline.  My car sat at the dealer for 10 days before the
replacements (all 6) arrived.  I just got it back Wednesday the 24th.

Incidently, my car was the third car in line waiting for the same
parts at my dealer.

BTW the coil provides spark not valve timing.

R.C.

Thanks guys!

I'll have it checked at an official BMW workshop. But what's funny is that
none of this malfunctions is detected by the diagnose tool...