Have a 2004 Cicic LX. This code showed when checked after warning light. Checked that the purge valve and vent valve open and shut respectively, when powered. Not sure how to evaluate the 2 way bypass valve. Working from home, nothing too sophisticated From things I have read online if this 2wbv appears to work it may be the fuel tank pressure sensor. Not sure how I can test that although from what I have read there is a measureable voltage output. Would need to know what voltage to supply sensor (12v?) as reference supply and what voltage the sensor should output. Does the sensor read vacuum or positive pressure or both? Also would need the proper signal voltage out through the applied pressure range. Assume the one tube on the sensor is just vented to air, the other to the tank pressure.

Regards the symptoms, since the warning light has come on I have smelled gas (a strong smell) once. Looking for help on how to evaluate the bypass valve functionality, then any information regarding the normal voltage readings and pressure range for the tank pressure sensor. Any help is appreciated Also tell me wha that pressure senso listed at $250, too much money to just try it Appears the bypass valve would be a dealer item as well.