PrUSA 3.5 upgrade - HOTEND HEATUP TEST FAIL

After 3.5 upgrade of Prusa 3+, the preheat test fails. HOTEND should reach 220 degrees in test yet stops at ~172. All component connections are correct. Hot end is unmounted so as to easily take measurements. This is only failure encountered. manual adjustment of nozzle temp works and attains correct temperature. Only the PREHEAT test is failing.