As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING PRE-TAXI CHECK WITH LEFT PACK RUNNING AND RIGHT PACK OFF RIGHT PACK LIGHT ILLUMINATED. ALL BLEED SWITCHED ON, ISO VALVE AUTO, TEMP SELECTORS WARM. GROUNDED - YES. REMOVED, INSPECTED & REINSTALLED RIGHT PACK TRIM AIR CHECK VALVE. NO DEFECTS NOTED. ISOLATED TO RIGHT PACK FCSOV NOT FULLY CLOSING. REMOVED & REPLACED RIGHT PACK FCSOV. OP CK NORMAL. REF FIM 21-62 TASK 856, AMM 21-51-01-000-805-002 & 21-51-01-400-802-002.