Optima 880 (2008 model year) Watch Dog Error

Hi all,

New to this site but browsed around and see some good stuff in here. I am hoping you can help me solve an issue that just cropped up today. My daughter used the tub last night and when I went out this morning to see the temperature, so I could turn it down, I saw the watchdog (------) across the screen. I went ahead and shut power to the tub for 30 minutes and that did not seem to help. What happens is that upon power up the temperature reads 90 degrees, and then about 10 seconds after that the watchdog dashes pop up on the screen. I read around the sen that maybe the temp sensor could be the issue? My question is what is the start up sequence for these tubs. Does it start up and look for the temp setting before it starts circulating water? Knowing this stuff may help me t/shoot this. The weather is getting close to freezing around here (high 30's at night), so I am concerned it may cause more damage if I can't get it heating again. I have tomorrow to dig deeper into this. This tub has been issue free all this time until this creeped up today.

Any advice would be great! :D