As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EMERGENCY AFT CABIN BULKHEAD AND CEILING EXIT SIGN LIGHTS AND CEILING AISLE LIGHTS FROM SEAT ROW 10 TO 17 FAIL THE 10 MIN FUNCTIONAL CHECK. REMOVED AND REPLACED BOTH BATTERIES IN EPSU #3 PER Q400 AMM 33-51-01-000-802, 33-51-01-400-802, OP TEST GOOD.