I need an ecu but dont know which model number I need. Mine is replaced with an obd1 and I want a stock one for emissions. Dealer said part number was 37820-P2e-A12 and I have found a -A02 on Ebay but dont know what the significance of the last 3 characters are. i have seen you guys mention P28, p06 and such ecu's but dont see any numbers like that in the dealer part number. Could someone help me out here? I have a 1999 DX 4dr standard.