P1259 A problem in the VTEC oil pressure switch or VTEC solenoid circuit
This is not a transmission problem, as this condition is common seen with the Odyseey You accelerate and the engine seems like it stumbles, The worse is when your at stop and as you accelerate it stumbles then runs fine. Clear the code do your normal driving, there are times when P1259 is set and it the EGR that causes the problem. What happens is P1259 is a type "A" code it suspends any "P" other code that would appear. For now replace the VTEC solenoid and the VTEC oil pressure switch. and don't be surprise if the next code that is set is for the EGR.