2008 250 needs head removed for a sensor??!!

[dobe4400]

I just relocated 2008 boat from FL to LA. Boat is rigged with twin Yamaha F250 4-Strokes, both with less than 150 hours. Sent boat to new marina for basic service, oil, filters, etc. Boat had a port side "Check Engine" warning flashing on digital tach. Marina is authorized Yamaha service center. Was told today that a "Sensor" was bad and needed replaced. In order to do so Head would have to be removed to install part. I hate to see engine "broke" apart so early in it's life, even though Yamaha is paying tab. Has anyone here heard of having to break-down a motor for any Sensor's replaced?! I'm not a Tech but that sounds extreme for a inexpensive Sensor replacement. Anyone with knowledge of such feel free to comment. Thanks
Dobe

[99yam40]

what sensor are they saying needs to be replaced?

Rodbolt should be able to help if you give all the motor info like model # of motor