The symptoms are:
The first time I was waiting for a green traffic light when suddenly the car wouldn't go. I looked at the OBC and the trans fail message was there. I pulled out the key and start the car again has if nothing happened. The second time the car did started running, but very very weak, as if it was running in the first gear. Same thing; I pulled over, pull out the key and started the car again as if nothing happened.
I took my 840 to the mechanic to perform a scanning after the OBC showed the message and the diagnosis was:
042($2A) Speed signal n-ab
I got the Speedometer Sensor - Located in differential
Part # : 62 16 8 357 020
will this solve the problem or should I'd be looking for something else?
Any help will be appreciated.