As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFT PAX CABIN EMERGENCY LIGHTS ILLUMINATE AFTER ENGINE START. NUMEROUS WIRES FOR EPSU SYSTEM FOUND CHAFED AND OPEN. NO STRANDS BROKEN - INSULATION WORN TO BARE WIRE. UNKNOWN ROOT CAUSE. REPAIRED ALL WIRES FOUND DAMAGED, SYSTEM FUNCTIONS NORMALLY DURING TEST AND ENGINE STARTS.