What was found
AUTOTHROTTLE DISENGAGED, WOULD NOT RE-ENGAGE. ACFT GROUNDED. PERFORMED AUTOTHROTTLE BITE/CURRENT STATUS CHECK AND FOUND NO CURRENT FAULTS. UNDER INFLIGHT FAULTS FOUND VARIOUS OCCURRENCES OF FAULT 22-31502 NO ASM DATA FOR ASM 2 ON FLIGHT LEG 17. PERFORMED FIM 22-31 TASK 805 INITIAL EVALUATION AND NUMEROUS SERVO MOTOR TESTS. NO CURRENT FAULTS FOUND. PERFORMED A/T OPERATIONAL TEST, IAW AMM 22-31-00. NO FAULTS FOUND. AIRCRAFT UPGRADED TO CAT IIIA AUTOLAND AND HGS, IAW AMM 22-00-01. CAT STATUS PLACARD SCREW MOVED TO REFLECT SAME.