71403

Short version - this was a running car that sat for about a year. Symptoms are no-crank / no-start - the cluster lights up and all other functions seem to work but there is no OBD2 scan tool communication at the underdash OBD2 port. It does communicate using the underhood X11/4 connector where it returns the following codes:

B1040 - fault in CAN.... with MR engine control
B1041 - fault in CAN... with traction systems

So far have checked all fuses, checked for water/rodent damage and found none including under passenger side carpet.

Would appreciate any ideas where to start next - have been looking for a diagram of the canbus and/or if there is a junction block for it like other benz but haven't found one.

bobterry99

When you twist the ignition key to start the engine the engine's controller energizes a small relay which switches power to the motor starter. I'd check to see if that little relay is energizing. It and other relays are in the main fuse box hidden from sight. To view them you have to remove a half dozen screws to lift off the cover to the fuse box. I don't know which relay is for the motor starter, so just listen for the sound of a relay clicking and/or touch each relay to feel for it's contacts closing.