What was found
CARGO FWD AND AFT FIRE SYS FAIL EICAS MESSAGE ON ARRIVAL AT 20,000 FT, BUT THEN WENT AWAY AT 500 FT. DECLARED EMERGENCY, LANDED WITHOUT INCIDENT. TROUBLESHOT IAW FIM 26-23-00-810-806-A00. R & R GEN I/O MODULE 3, MAU3-MOD 9/10 IAW AMM 31-41-06. OPS CHECK GOOD.