[gprsh924]

Did some searching on the bimmer forums, but found very little info.

Earlier today, my E39 flipped into "Trans Failsafe Program" at a stoplight. I had to limp back to my office in 3rd gear. A few hours later when I left work, I started the car back up and the trans failsafe message had gone away but my Service Engine soon light came on. I stopped at Autozone on the way home and had them run the code.

It came back as P0721 -Output Speed Sensor.

I drove carefully all the way home and tried to notice anything that felt off about the way the car was driving but I did not feel anything. My quick research indicates that this could be a bad sensor, a sign of low transmission fluid, an actual problem with the transmission, or even possibly a bad battery/alternator that is messing with the trans codes.

Anybody with help or experience here? Clearly I am going to need to get this to the shop and have it looked over. My family uses a small shop in the suburbs for most of our work and the mechanics/owner seem straightforward and honest, but I still like to know what direction my wallet is heading before I drop the car off.

Thanks in advance.