Engine codes PO455 and PO521
On the PO521, havent been able to find all that much besides the oil pressure sensor. oil level is good. changed very recently and regularly.
any suggestions?
Thanks a lot!
https://ls1tech.com/forums/ls4-perfo...0521-code.html
As for the other code check the canister on top of the intake manifold at the back toward the firewall for cracks or the lines going to it.
I replaced both parts and it fixed all my problems and they were about 15 minutes altogether to do
I ended up replacing the engine a couple weeks later

Hope thats not your case..... best of luck


