As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: DURING BITE CHECK OF CIDS-1 EMERGENCY POWER SUPPLY UNIT TEST CLASS 1 EMERGENCY POWER SUPPLY UNIT 12WL EMERGENCY RIGHT DISPLAYED EMERGENCY POWER SUPPLY UNIT (12WL) EMERGENCY RIGHT / DECODER ENCODER UNIT (DEU)-B (300RH6). MAINTENANCE REPLACED DECODER ENCODER UNIT (DEU)-B (300RH6) AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK.