2001 Ford Escape codes P0455 and P0457. Which sensor(s) havein gone bad?

Question

Codes point to a bad gas cap. This is false because I have bought and used two new gaps, one from Ford and one from JC Whitney that actually seals. This is probably a sensor. How can I know which one without sending Ford on a costly little fishing expedition?

Answer 1

You can have the evap system smoke tested. Any shop can do this and locate the leak. Most of the time on this vehicle the problem is with the vent control valve or the wiring to it. It sticks open and causes the code to come up for the evap leak.