Pontiac Repair: p0401 96 Trans Sports 3.4L, pwm signals, egr valve

Question
I read all your articles on this subject and I have the following questions.
P0401 does not indicate a PCM problem with the Quad Drivers. PCM protects itself if a overload or short to the EGR valve occurs. Thats great news as I thought I needed a new PCM to repair the EGR control.
I cleaned and bench tested the egr valve and it checked out ok. I cleaned the port to the manifold but I did not clean the hose going to the exhaust pipe. Should it be removed and cleaned as well?
If the quad driver failed, wouldn't I get a different DTC code?
Finally, how can I perform the 25% 50% 75% and 100% test from the PCM without an expensive scan diagnostic tool? Could I simply be missing a ground that the quad drive requires to drop the PWM signals to the EGR?
Thanks for your help you are the Man!!

Answer
Hi Sonny:

well a couple of things. the pipe NEVER plugges up in the exhaust. The port in the manifold does. You can't command on the valve with out a scan tool. Just because the valve will open and close when you jump it doesn't mean the valve is good. If the current draw of the valve is more than what the PCM is expecting it will trip the code. A quad driver is basically a solid state internal relay with a ckt. breaker. if the draw is to much or not enough it will turn on the lamp. Hope that helps you out. Good luck :)