Was sitting at the grocery store with Grandson waiting on the ol' lady to finish shopping...Was playing the radio and the motor was not running at the time. After about 15 minutes of shopping, I finally started the car and received a message that the car had Reduced Power. I continued to drive for about 5 miles and everything cleared-up and came back to life...Could this be an indication of the alternator ready to take a dump or possibly something major? It has done this before, but has always managed to rid itself after running the car for a couple of miles. Tuner also said that it may be an alternator; wanted to try the board to see if any other 2008 535 owners had any like experiences...

 

Had it twice in the 6 months I've had my '08. Turn the car off, then back on, and it seems to go away. Also had the steering alert come up too.

 

research high presssure fuel pump or "hpfp" problems. the n54 engine, especially early models like the 08's have a history of fuel pump failure or corresponding parts, sometime a misfire of some sort. the good news is bmw extended the warranty for n54 engine it's hpfp to 10 years, 100K miles...take a trip down to your bmw dealer and it's service department....have them diagnose the problem......

had the same error twice with my 08 535i....went in for service, resolved after the second try

 

I had the same issue. I restarted the car a few times and it would usually go away, however it would always keep coming back. In the end, for me at least it was the high pressure fuel pump that needed to be replaced as Gene suggested. I took it to my local dealer and they replaced free of charge.

 

I had the same issue and turned out to be a VANOS solenoid issue. Lucky for me i caught it right before the warranty ran out.

Same symptoms though, except mine came out under full throttle. turn it off and back on and it goes away. Glad the dealer was able to diagnose it.

 

Had similar issue with my 2008 535i. Water pump needed to be replaced.