The real reason why i joined this forum

The missus has driven her beloved mini twice now and gotten the gear shaped icon light on the tachometer in orange with the exclamation point. I had it taken to a shop and dropped off only to have them tell the guy tell me he couldn't pull that error back up and didn't read any error codes.

She drove it again last night same thing starts flashing again. She pulls over puts it in park, shuts the engine off, turns the engine back on, error isn't showing up and drives off again just fine.

I am convinced there is some sort of a sensor or shifter problem but not sure where to start troubleshooting.

Any help is greatly appreciated.

Thanks,

Ian