Perfect Pass Temperature Calibration

[Shoemaker Mobius]

We have Perfect Pass on our Mobius LSV and by hitting Menu and the up key at the same time it displays the lake water temperature. This has been very valuable in determining wet suit usage or not and from the factory the temperature reading seemed right on. However, last weekend we took the boat out after not using it for about 4 weeks due to foul weather and the temp reading is about 10-15 degrees too high. During the four weeks the boat was in outdoor storage on the trailer with the boat cover on - that's how we store it every week. I know the temp reading is off because the lake is usually in the 55-65 degree range and the display was showing 70-78 degrees. Any ideas on why the reading would be off? I realize that you can recalibrate the temp, but that means figuring out what the temp really should be and setting the temp display to match. I don't understand what would have caused the temp sensor to misread. Anyone else see this?

[lowdrag]

Is there any chance that you were estimating the temperature of the lake to be a little too high. This is just a guess, but maybe the perfectpass can be switched between Celsius and Fahrenheit and somehow it got changed or reset itself.

[Shoemaker Mobius]

No, the temp gauge was 14 degrees too high. We went out yesterday and I took a thermometer with me. The water temp on the thermometer read 64 degrees, but the Perfect Pass display read 78 degrees. I recalibrated the PP temp gauge, but I still would like to know what caused the gauge to go from reading accurately to 14 degrees too high.