How can both PO452 and PO453 codes both occur for 2004 Buick LeSabre during emmission testing

Question

I read your info for each, but don't understand how both codes can be activated.
Thanks

Answer 1

P0452 Evaporative emission control system pressure sensor low input

P0453 Evaporative emission control system pressure sensor high input

The code condition would just be a coincident when the code was set, It could of just happen driving down the highway. In order to have both code this is a definite failed FTP (Fuel tank pressure ) sensor