I never bother with the MES built in meat probe.I have a 40" 2.5 gen. Works fine with the only weak spot being the temp prob. I think it's because it's holstered in a metal bracket that shorts out the prob. I have a Weber dual prob that states in the instructions to avoid contact with metal when in use to avoid shorting it out. I drilled a hole in a chunk of wood that it rests in, so far no more issues.
Now easy way to check it for accuracy anyway. I just leave it in the sheath, and use my Mavericks.
Bear