slapshot30

I'm throwing both codes in my 05 GXP. replaced the gas cap and that fixed the PO455 for about a week. Now that upped to a Large leak. I've read to change the EVAP canisiter or changing the fuel pressure sensor. anyway to determine which isn't funcitoning?

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!

Hawkins04

iTrader: (4)

i had the p0521 code aswell and it was the oil pressure sensor.
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

slapshot30

Thanks much for the response and advice.

hazards280

I had the P0521 a couple months ago , I ended up changing the sensor, which ran me about $60 at the dealer and the code was still there. I then had the oil pressure checked and it was idling at about 6psi.

I ended up replacing the engine a couple weeks later

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

slapshot30

got my fingers crossed lol