1995 baja 272 454 mag efi had problems running wot when engine was warmrd up got home and checked the codes 1. read coolant temp low temp the second one was mat signal voltage high should i go ahead and just change them both they where changed last year or does anyone know why the map would would read voltage high

first you wrote m.a.t then m.a.p . if its a mat , iy may have been set due to improper winterizing. same for the coolant temp. is there a stat and is it working.