Yamaha F350 won't shift into gear

[BrentJ12]

Motor runs but won't shift into gear. Code 123 Electronic Throttle System and code 155 Shift Position Sensor both appear. It appears these are keeping the shift actuator from working. I checked fuses at the motor and shift actuator was not blown and there was power to fuse.

Is there some further trouble shooting I could do? Motor is one of a pair and the other motor is not having issues. I could probably do a sensor swap from good motor but don't even know where to start.

Motors are under warranty but getting the boat to a launch ramp on one motor is not safe given the honking winds we are having. Would appreciate some advice and / or pictures of where to find these sensors on the motor.

I'm chasing a mobile mechanic but he is buried right now....

[Sequoiha]

Might have to do a control box reset, at key on are the blue LED's on, on the control box.

[rodbolt17]

not much you can do with it in the water.
don't even think about sensor swapping.
I have only seen 1 failed shift actuator.
I have done way to many shift shaft bushings.

the bushing is in an AL carrier and the shaft is steel.
once the busing gets to tight the shift actuator cannot push it.
bushing costs about $3.10, requires powerhead removal to change it.

if you get two blue lights when idleing in N and the yellow when shifting then watch the actuator when someone moves the helm lever.

at a MINIMUM make sure your moble guy is a Yamaha master tech.
the F350 is NOT a backyardigan/have tools will travel tech friendly.

[BrentJ12]

Some more info

I remembered some more info that may or may not help with further diagnosis. Before I discovered the shifting problem I had a low battery voltage warning. I attempted to charge batteries by running motors at idle as the batteries are buried and require some dismantling to charge. This seemed to clear the warning but then I discovered the shift problem. Figuring they may be related I got access to the batteries and fully charged overnight. However fully charged batteries didn't resolve the issue. Should I attempt a control box reset to rule this out? If so, what is the procedure into initiate a reset?

Both lights on the control box are blue when key turned on initially. At some point during troubleshooting (attempting to shift into forward and reverse) the starboard side light turns orange I'm guessing triggered by the error codes that also appear. When motor turned off then on again the codes clear. I have had a helper attempt to shift while I watched the shift actuator. At first I thought there was no movement but after watching further it does appear to rock slightly it just doesn't actually move forward or back.

Any of this new info help with further diagnosis?

[rodbolt17]

a control box reset is done with the laptop and YDS.

when you shift have someone try to manually move the shift shaft in the actuator fwd.

there are some voltage checks for SPS and motor actuator.

most likely your going to find a corroded bushing,hope not.

the SPS is part of the actuator.
the only way to access the actuator is by removing the powerhead.

DO NOT even attempt to pull the shift shaft pins.
no point in it as the slide pin wont drop low enough to clear the actuator.

and never EVER ask my opinion of the F V8.