Out of the blue our ML320 has decided not to shift out of 1st gear. It will drive around just fine in 1st gear, but we can't go anywhere obviously. The ABS, ETS lights are on.

The code reader showed codes for the brakelight switch, which I replaced today and there are 2 codes related to the rpm sensor:
C1100 Rpm Sensor FL
C1100-016 Rpm Sensor discontinuity

Also, when trying to access the ME2-SF1 Motor Electronics heading on the scanner the tool reads, "Fault in communication with ECU."

When first hooking up the scanner it "hints" at the Electronic Selector Module.

This transmission has always driven great. There are 200K miles on it, but it was always serviced and flushed a year ago, refilling with new fluid. I have a feeling there is something other than the tranny preventing this thing from driving.

Any ideas? Is the Rpm Sensor located within the conductor plate? I know there are 2 sensors inside of the conductor plate, but I don't remember what 2. Maybe transmission speed sensor and Rpm sensor?

Any help would be greatly appreciated. Thank you!