1999 Silverado 5.3 Code P1415

[Jim60]

I have a P1415 code for a check valve driver side, I replaced the valve code went away, and 500 miles later code is back again. I removed the check valve and inspected it checked it with shop air it held and did not leak, removed the tube and checked for restriction nothing found, replaced the gasket 

Started engine same problem 

What am I missing?

[Jsdirt]

If you live outside of CA, I'd throw the entire system in the trash and put electrical tape over the "money" light. Especially on a quarter-century old truck. Sell the new part and the rest of it on eBay - someone in CA will probably buy them. 

 

I never got into troubleshooting those since that's where every single one I've ever seen went.