8D IKE: EGS signal line disturbed, M54 3.0

[kfm]

My 2002 X5 3.0 (65K miles) developed a shifting problem where after driving for about 4 to 5 miles it would make a big jolt down shifting from 3rd to 2nd. Trans failsafe message also shows up.

Upon downloading the error code, I found:

53 DME signal, crankshaft sensor,
F4 DME Segment timing, true running disturbed,
96 EGS CAN engine speed, and
8D IKE EGS signal line disturbed.

My question here is, could this be a bad crankshaft sensor?

At first I had missed the last error code so mostly been focusing on the crankshaft sensor. I have this nagging doubt that crankshaft sensor is really the cause of the shifting problem. From all I have read of people reporting crankshaft sensors errors none was associated with shifting problem. They all related to engine problem like not starting or running rough. My engine starts like charm and is running perfectly fine. Also, if crankshaft sensor is the problem why only 3rd gear downshift?

Recently I went back to the error log record (pictures taken of the scanner displays for each error) and realized I had missed the EGS signal error. Researching on that led me to a long thread on a 4.6 that seems to indicate my problem could be electrical.

Now I wonder if it is worthwhile for me to replace the crankshaft sensor to see if it fix the problem?

Would most appreciate any advise!