As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RIGHT PACK TEMP EICAS MESSAGE ILLUMINATED, AICRAFT BACK TO GATE AND TAKEN OUT OF SERVICE BY MAINTENANCE. REPLACED TEMP SENSOR TS199 IAW AMM 21-58-08 POST INSTALLATION TEST NORMAL R PACK TEMP CONTROL OPS CHECK OK IAW AMM 21-51-00/501 A/C UPGRADED TO ETOPS 180 PLACARD REMOVED