Wrong temp reading on heater sensor (2 replies)

I have a DIY printer with Marlin 2.0, an Arduino MEGA 2560 and a RAMPS 1.4. It has two of the same temperature sensors in it that read differently by about 11 degrees. If the bed reads about 20 degrees (which is the actual room temp), the extruder reads about 9 degrees. I tried a 3rd sensor in the heater with the same result.

Is there a way to adjust the temp reading up by 11 degrees in the firmware?