iStat Menus is a helpful diagnostic for this one! MBP 15" Retina mid 2015 11,5 After a battery replacement, very slow , Fans running fast, CPU Kernal High. Apple Diag code PFM006 (Problem with SMC). PRAM, SMC, reset no effect. iStat Menus shows sensors Palm rest - Palm Rest Actuator - I now know that " - " indicates a missing or bad sensor reading. All the suggestions above did not fix it. I had to replace the TrackPad to Motherboard cable. The iStat Menu sensor now displays the "palm rest" sensors correctly at around 30 deg, and the problem is fixed. Part came from IFIXIT USA. Item 117088-1 MAcBook Pro 15" Retina (Mid 2015) TrackPad Cable / New
