P0135 - O2 sensor, upstream front P0155 - O2 sensor, upstream back P0498 - Evap vent valve voltage lowThe O2 sensors are fairly easy to get to, so hopefully that will be easy. However I have read online that there is some honda troubleshooting chart that links these 3 codes. Why would oxygen sensors and the Evap valve be linked? We may find out the hard way.
The evap vent valve is normally open and is so to allow you to fill up with gas. As gas goes in, vapor must go out. If the valve is stuck shut, you may have the gas fill click off frequently. The vent valve is under the vehicle (under the driver seat on the Odyssey, accessed from under the vehicle) and near the gas tank.
DO NOT confuse the vent valve with the purge valve!
There is also a purge valve near the intake manifold, but that is unlikely to cause the P0498.
Also broken hoses and wires can be the problem, as can the gas tank pressure sensor, but the latter will probably throw a different code.
The second video replaces the purge valve, not the vent valve.Tom's Camry pages / tom@mmto.org