Ok, I downloaded the 3800 service manual. It says this about the 150C error: "The APG sensor cannot detect the origin point when the APG motor has driven for a predetermined time period." I then says: "Replace the APG motor (MOTOR, ASSY, APG). See 4.3.5.1 MOTOR ASSY., APG on page 118. Replace the APG sensor. See 4.3.6.5 APG SENSOR on page 129."