Sorry to revive on older thread - but this seems to be a pretty common fault so nothing gained by starting a new one.
Today I've had exactly the same fault as described by the OP. On a 2007 335d E90 with 22.4k miles covered since new.
What's the betting I get stung for a large sum of cash as I only took out the BMW insured warranty 2 days ago and BMW don't offer me any goodwill on a part that's only lasted 22000 miles !
Hopefully it's just a sensor but I'm going to bet hydro pump etc ...
Have to say Rybrook BMW in Warwick have been superb as always after I rocked up at lunchtime today and they dropped my off to my office then got me in a loan car by 6pm tonight
