if its the check engine light, it can be becasue of atleast several dozen reasons...not just the few mentioned above.
the owner's manual will offer no help...as manuals will only tell you to take it to a shop. if you can tell me exactly how many times it flashes and for how long it stays on....i can look up into the honda hayne's manual and can tell you exactly what the problem is.
the engine light turns on based on a code...there is a code for a host of problems that the ECU may detect.
the proper way to resolve this is to plug a code reader in the ecu and it will show up the code. then that code has a definition that a honda mechanic can look up and diagnose properly.
hope it helps.