What was found
AVIONICS SMOKE ECAM MESSAGE DISPLAYED AFTER STARTING FIRST ENG. REMAINED AFTER SECOND ENG STARTED. SHUTDOWN ENGS & RETURNED TO GATE. RESET AEVC SYSTEM, NO FAULTS FOUND, AEVC TESTED OK. RAN BOTH ENGS, NO MESSAGE OR FAULTS. NO SMOKE NOTED IN AVIONICS OR CARGO COMPARTMENTS.