2004 BMW 525i transmission default mode constant issues since 70K miles at 112K now

[bjonsey55]

I have a 2004 BMW 525i as second owner since 2006 with 20K miles (from Long Beach BMW), car was great until about 70K miles and car goes into "limp mode" transmission default. But it will reset to normal by turning the car off, removing key, and restarting but recently since 100K miles I have to reset codes to get it out of "default mode" at times. but car still drives and has since 70K miles. I am not a gear head and don't know anything about cars. But i did see a You Tube video where a guy was explaining that this is a common issue with 2004 525i and it is not the transmission but a computer communication error and mechanics/dealers will want to replace the transmission. However, I cannot find the youtube video anymore. Does anyone have an idea what it is and where I can have someone look/fix it? I'm in Huntington Beach California, Please HELP, Thanks

P.S. i have pampered this car with all scheduled maintenance and NO racing.

Also, if it was the transmission, I figure it would have went out a long time ago, not 50K miles and still driving well at times currently

[bronson75]

You'll need a BMW-specific code reader to get the diagnostic codes, standard OBD reader won't do it.
I was having similar issues on my 525xi, turned out to be the crank position sensor. I have a couple detailed threads under my same username here:
https://5series.net/forums/e60-discussion-2/

Sent from a Galaxy far, far away.