Hey all,

I have a 2000 Monte Carlo LS 3.4 with a PENDING P0405 DTC code.

Yesterday, I had a P1404 code, and I replaced the EGR valve. Once I replaced it the trouble code P0405 showed up. I reset the code, and it immediately came back. I tried disconnecting the battery as well but the code remained.

Can anyone advise me on what I can do?

Thanks!

 

I am going to perform the ODB II GM Drive Cycle and see if the DTC clears by itself. I will post the results here.

 

Have you double checked that the harness connector is clean and tight? Also, was the mounting surface completely clean, no engine grime or dirt etc..

Also, after thinking more about it, when I replaced mine (3.4 engine also) I didn't have my own scanner at the time. Used a friends and he told me to erase the code with the egr unplugged so the computer would relearn it's settings from scratch. Probably similar to what I have seen people say about the relearn needed if the throttle body is replaced. He is a Ford mechanic but his advice worked perfectly for me.