As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI, (L) PACK OFF CAUTION MSG. CREW RETURNED TO THE GATE (BTB). PERFORMED BITE TEST AND RESET OF BLEED SUPPLY MODULE FOR PER FIM 21-51 FT 844 NO FAULTS NOTED. PERFORMED ENG RUN PER AMM 71-00-00 ALL OPS CKS GOOD AT THIS TIME. AIRCRAFT REMAINS ETOPS 180. A/C RETURNED TO SERVICE.