Hi there,


I am scratching my head on this one, not something I like doing! For the past little while I've had quite a few issues with my Monte Carlo and its EGR.

I got the codes

P0403
P0404

So I cleaned the EGR Valve and pipes to clean out any possible carbon. This did not fix it. SO I bought a new EGR Valve. Installed in and P0404 left but P0403 remained constant and has become a hard code.


I currently work on a base that has an auto club in which mechanics volunteer their time to help others fix their vehicles or tune the rides whatever the case maybe and we have all been scratching our heads trying to figure out what has been the problem. I also replaced both 02 sensors and sealed an exhaust leak that was found behind the cat (As its the stupid 1st generation U-pipes) The P0403 remained and the code will not leave no matter how many times I've rest it. A few people have mentioned the fact that it might be a bad PCM is this true?

There is no broken wires at either harnesses.



Thoughts?


Thanks!