2011 x5 35d reduced power light
 

I have a 2011 35d with an occasional engine light that says reduced power. When the light come on in the display screen the engine goes into a reduced power mode. When I slow down to about 50mph the light goes off and the engine goes back to normal operation.

I am a tech and own a diesel injection repair business so I am very familiar with domestic engines and the fuel system on this car. However I have never run into a situation like this.

Last week when driving 240 miles home from my Montana vacation home this happened about 6 or 8 times. I can feel it in my seat a little bit before the light comes on. I would call it a bit of a surge or fish bite feeling but cannot see it on the tach. If it was a Duramax or Dodge I would swear it was a plugged fuel filter.

This has been happening on and off for a month. I changed the air and fuel filter soon after it started but has made no difference.

After this "reduced power" showed in the display several times the engine light came on and stayed on. The next morning when I went to work the light was off and the thing ran fine all week around town and on one 60 mile round trip on the highway.

I drove it back to my vacation home on Friday and I could feel a bit of a surge a few times but no light this time over the 240 mile trip. The thing runs fine and there was a couple of times I had it well past 120mph for some straight away stretches with no problem.

Anyone run into this?? It is under warranty and I have had it to the dealer but they cannot find anything.

If the MIL is lit at any time, there is a code stored. What does the dealer say the code is?

Do you have access to a quality scan tool or other device that can show EOT, ECT, TFT? Maybe you have an overheat issue.

Agree that there should be a code stored.

"cannot find anything" can mean "we found some stored codes but no present codes".... reasoning that they wont replace parts until it is a constant failure.


Also, BMWNA can occasionally instruct dealers to just return the car and see if it comes back- so an owner might need to come back 2,3 times before an expensive repair is undertaken.

Force them, in writing, to report any and all codes to you.

Also, there are diesel subforums where you'll find more Dheads. Bimmerfest too.

GL

A

This has happened to me.

Strangely it was just after the dealer serviced the car. After driving off the lot I got the reduced power warning. I pulled back into the lot and SA had a tech come check it out. Apparently they did not securely reconnect some wiring. I don't really know which ones.

So before you go replacing things, I would make sure that all the wiring harnesses are plugged in tight and securely attached.

Good luck.

Had this happened to me, I'd have insisted they write up a new work order; pull the codes and report them in writing; fix it; clear codes. Plus it makes them take responsibility for their work.

If they didnt clear codes, the next time something comes up on the car the old codes MAY still be there, confusing the issue.

Just FYI.