I have no experience with an AE except for sitting on one at my Dealership. I looked in my Service Manual and Fault Code SH_26 indicates abnormal clutch movement when the main switch is first turned ON (clutch motor current is too high when automatically disengaging the clutch prior to start-up). The bike is unable to start or run if that Code is detected. Ok nothing new there for you except frustration and loathing. The high current could be from a hydraulic or mechanical problem I believe. Unfortunately they don't describe the desired current specs anywhere that I can find. Involved are the actuator motor, slave cylinder, hydraulic system, and of course the clutch actuator rod assembly and clutch pack similar to the A models. Any high system hydraulic or mechanical resistance could cause a high current demand in the clutch motor. I'm not sure what a high electrical resistance from corroded connectors would do to the clutch motor assembly. Note: the auto clutch components are controlled directly by the MCU (AE's motor control unit).
The Manual says that the clutch actuator test procedure (SH_63) cannot be enabled in the AE Diagnostic mode if SH_26 is called = can't even test the clutch actuator with the 26 Code detected. You have to fix potential problems and erase Fault Codes as described before the auto clutch can be tested and/or the bike started.
Next, for SH_26 it says to:
1. Check for clutch fluid leakage and correct level.
2. Bleed any air from the clutch hydraulic system and check for clutch stroke (I assume that involves either examining the clutch pack or setting the movement described in SH_66).
I presume the Dealers you've taken the bike to have done these procedures and the problem still exists? Did they document what they've done? What did they do?
Does the bike just flat quit when underway, or just refuse to start after a run at key-on?
If the bike were mine and I had access to a Service Manual I'd do just what Yamaha suggests as a service procedure, confirm the Fault Code(s), then erase any present. Then do the clutch and gearshift setup test procedures SH-63 to 66 as described. That should set the bike up properly. If it then fails, it may be due an electrical connector or component problem, and not a hydraulic or mechanical issue.
As some have correctly suggested, check for proper connector coupling and grounding of the YCC-S system.
That's what should have been done so far by the servicing personnel in my very humble opinion. Anything less is just shotgunning the problem. For some, every day's not Christmas, and every night's not New Years. Grind away at them and best of luck with Yamaha Corporate.
Gary in Fairbanks