Update to the situation. So all seemed fine - but then Friday - the horrific beep and error code. So, all my throttle work was for nothing. That meant the only issue was the HCU (helm control unit). I called the local Volvo service - they said they were not authorized to sell or install the HCU - huh - said they will call Volvo Tuesday and find a solution. So, I then started looking closer at the problem, I could touch the wiring harness and the problem occurred. So this meant most probable a connection issue. Well about 3 hours of isolation - I proved it was a connection issue inside the HCU. Well, I'm an electrical engineer that designs computers, so I cut the unit open and dug through the potting material exposing the very poorly soldered connector. I touched it up and re-sealed the unit. And presto . . . I can tug on the cables and unit all day and no error. I surly hope this fixes it once and for all . . . this has been a long year of boating . . not knowing when the error will occur and not getting any help from Volvo service. Long ago I really would have spent the 2k - 3k to fix the problem - but no one knew how to diagnose the issue. I think I know what I will do in my retirement . . . I'll be a Volvo EVC service guy - there is obviously no one that services them.
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2010 Vista 338 Volvo Penta
2005 Yamaha Wave Runner FX HO
2005 SeaRay 280 SunDancer
2001 SeaRay 245 Weekender