As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: LEFT 2 MID EMERGENCY POWER SUPPLY UNIT INOPERABLE, DURING CIDS OPERATIONAL CHECK, TASK 33-51-00-710-001. MAINTENANCE REPLACED LEFT 2 MID EMERGENCY POWER SUPPLY UNIT PER AMM 33-51-38 AND PERFORMED SATISFACTORY OPERATIONAL CHECK.