735il 1991 question

[atv087]

i was wonder what the button on the side of the shifter was
if i press down it goes to m and if i press up again it goes into s and then if i put it in drive it goes into E i was wondering if anyone knew what it was and how to work it?

[dlog]

I believe this is the overdrive switch. You may what to get a second opinion though as I haven't research this, only experimented on the freeway w/ it.

[Bear]

Pretty straight forward:
E=Economy mode (all gears +overdrive).
S=Super (raises RPM of the shift points and eleiminates the economy function), you want quicker accleration go to S.
M= manual (allows you to start in other gears and locks you there) willnot over rev so not too worry.

[atv087]

so i can get it into super mode when in drive and it will accelerate quicker?

[Bear]

Correct, if you go to "S" when cruising in "E" the transmission will drop out of overdrive, your RPM will raise and you will be able to accelerate quicker.

[atv087]

thanks. Also i get an eml light once in a while it goes away after long drives but for short trips it comes on often and it feels as though the car does not go into overdrive any idea what could cause this?

[Bear]

I would keep an eye on the alternator,if that is going it will give an EML prompt and may put you, momentarilly, in LIMP Mode. Try this (it may work on your car), hit the 1000 and 10 numbers on the OBC at the same time, the OBC should read TEST. Then using the number key scroll down until you reach #9, then hit S/R and you should read either battery voltage (with engine off) or Alternator voltage with engine running,(voltage on alternator should be between 13.5 VDC and 14.1 VDC). I did this while driving and every time the car wnet into limp I looked at the OBC to see what my alternator voltage was reading. also, a bad MAF will put you in limp mode, I had this happen on my1988 750 until I was able to sort out the problem, I put in two used MAF, and that solved my problem.