I have a 01 Toyota Avalon xls with a c1301 and p0441 codes. What causes this and what is needed to fix?
The 1301 code is a byproduct of the p0441. You have to start by diagnosing that.
Is the gascap loose?
Do you have a scanner, so you can active test the vsv's?
Gas cap was replaced. Isnt there a tsb on these 2 codes showing up together?
Yes, the 1301 is a byproduct of the p0441 code. Once you diagnose and repair the 441 code. the 1301 just has to be cleared.
Will see if replacing the cap takes care of it. Do you have a copy of the tsb?
I don't think the gascap is causing the problem, It most likely has a faulty switching valve. It has to be diagnosed. That is not something that can be done via internet.