EGR question 96 Grand Prix 3100

[echo1999]

Hey all, I have a 3100 V6 Grand Prix. I have had the SES light on for a while, took it to autozone and told me it has a P0401 "defective egr valve or insufficient flow". I took off the egr valve and replaced it with a known good one, cleared the code and 10 mins later it came back on again. I removed the egr valve, left it plugged in, started the car and it appears to not be operating at all. So now in thinking wiring? I presume the egr should start working when the car is running.

Any thoughts?

Thanks

[PCGUY112887]

Did you check the intake or even the EGR tube for crap buildup that could be blocking it?

If it was electrical, seems like you would get a code about voltage on the EGR.

[echo1999]

Found this guy at automotivehelper.com, I have the exact same problem after removing my intake and peeking inside the TB, here is a post once he found the problem:


FYI,

I would like to thank you for the assistance. I finally took time to remove the throttle body to see if there were any clogged ports. I found the problem as soon as I remove the throttle body. The port leading to the EGR valve was very clogged. The carbon had accumulated so much that it looked like a ball of rubber and or asphalt. I cleaned the port with carb cleaner. Had to use a clothe hanger to penetrate the carbon by running it through the port beneath the EGR valve. I didn't noticed any other carbon buildup except for the plate of the throttle body. I certainly hope that I removed all of the carbon to prevent the MIL from coming on again. Now I understand why the scan tool was telling me "insufficient EGR flow." I noticed that the port that was clogged is very small in diameter. I was expecting it to be larger. Thanks again! Take Care!

I just have to get the time to remove those damn heater hoses from the TB, while I am there I might as well replace them as well as the thermostat.

[ForcedFirebird]

Hey all, I have a 3100 V6 Grand Prix. I have had the SES light on for a while, took it to autozone and told me it has a P0401 "defective egr valve or insufficient flow". I took off the egr valve and replaced it with a known good one, cleared the code and 10 mins later it came back on again. I removed the egr valve, left it plugged in, started the car and it appears to not be operating at all. So now in thinking wiring? I presume the egr should start working when the car is running.

Any thoughts?

Thanks

Hmmm, this is happening on two of my vehicles. One of which I ignore, the other is because ther is no EGR on it (had to make room for the turbo .

It doesn't affect my driveability or mileage, just have to put up with the light and check my codes once in a while.

If you replaced the origional with a known good one, you probably have carbon build up. Take your plenum off and clean it good, along with the EGR tube that goes to it.

Also may want to check the exhaust manifold to EGR gasket.