What was found
NR 1 A/C PACK OVERHEATED, STAYED AT 100 DEGREES. ECAM MESSAGE APPEARED DURING TAXI, RETURNED TO GATE. FOLLOWED TSM 21-52-00-810-820-A, SYS RESET AND PERFORMED SYSTEM TEST OF TEMP CONTROL SYS ON MCDU (ATA21) AND THEN TEST OK. OK FOR SERVICE IAW TSM 21-52-00-810-820-A.