so what can i do to fix it?

Question

my Honda odyssey did not pass the smog because of these two codes p0325 and p0730.

Answer 1

P0325 Knock sensor circuit failure

P0730 Problem in countershaft speed sensor circuit

The knock sensor code , you can set that if there is low coolant level  or water what ever is being used. Or low motor oil motor oil, level in the half way mark is which is safe is fine, Do those first making sure the radiator and the cooling system is proper and the motor oil , clear the code, and set the monitor , Both these code may just be intermittent As for P0730 the countershaft speed sensor may have to be replace , but cleared the code and set the monitor for the emission test and no Heavy foot on the Pedal.