As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RT PACK TEMP EICAS MESSAGE DISPLAYED PERIODICALLY DURING CRUISE FLIGHT BUT WOULD EXTINGUISH IN 5 SEC. REAPPEARED IN THE DESCENT. TURNED SWITCH TO AUTO-N IAW QRH. MESSAGE DID NOT APPEAR IN AUTO-N. PERFORMED PACK TEMPERATURE CONTROLLER BITE PROCEDURE IAW FIM TASK 21-51 FAULT TREE 803. NO DEFEECT NOTED. OK FOR SERVICE.