Service Engine Soon - Insufficient EGR flow

[BIGPROFITT]

Does this theory make sense to you:

Map Sensor seal is bad so PCV valve closed not allowing proper ventilation. This creates the vacuum, which in turn does not allow the EGR valve to open, or sticks closed. Thus causing the error code.

[BNaylor]

Originally Posted by BIGPROFITT

Does this theory make sense to you:

Map Sensor seal is bad so PCV valve closed not allowing proper ventilation. This creates the vacuum, which in turn does not allow the EGR valve to open, or sticks closed. Thus causing the error code.

No it does not. The MAP sensor is just a sensor. It has nothing to do with how engine vacuum is developed or PCV valve operation. You could block off the MAP sensor hole on the plastic retainer and the engine will work fine until MAP values are required for normal engine operating conditions and diagnostics. Remove MAP sensor fron the retaining clips and put your finger over the hole. Also, the EGR valve will open or close regardless of what the MAP sensor is doing. It has its own parameters for operation. If your MAP sensor seal is that bad you should be able to hear it audibly in the form of a vacuum leak. Also the engine idle will be very erratic and engine may stall.

[BIGPROFITT]

I just looked at the PCV valve again. The big orange oring is on there and in good condition. The black oring that actually goes around the pcv valve is completely missing. Could this cause the problems I have been having? Thanks.

[richtazz]

As bnaylor3400 stated twice before, a missing or damaged lower black o-ring on the PCV valve WILL cause the p0401 code. Get a new lower PCV o-ring, reset the code and you should be good.

[BNaylor]

Originally Posted by richtazz

As bnaylor3400 stated twice before, a missing or damaged lower black o-ring on the PCV valve WILL cause the p0401 code. Get a new lower PCV o-ring, reset the code and you should be good.

Right on Rich!!!!!!!

[BIGPROFITT]

I know, I know, I can be thick-headed some times. I do really appreciate all the help from both of you.

[richtazz]

No problem BIGPROFITT, that's what we're here for. Sometimes you can't see what is right in front of you, especially when you're frustrated working on your own car. You are forgiven for your brain fart moment.

[troy1]

If you cant figure it out and don’t wana throw high dollar parts at try ED > [email protected] great guy with cheap used OEM parts. he should have EGR valve and MAP sensor galore.

[BNaylor]

Originally Posted by richtazz

No problem BIGPROFITT, that's what we're here for. Sometimes you can't see what is right in front of you, especially when you're frustrated working on your own car. You are forgiven for your brain fart moment.

Cut him some slack Rich. If a poster wants to take 5 days fixing what amounts to a less than 30 minute fix thats no problem with me. No skin off my hide.

[JBent9610]

For what it's worth, I had the same code for a long time on my Grand Prix. I tried cleaning the EGR valve and replaced the EGR gasket, but nothing worked. I then took off the cover of the PCV valve to check the rings. I tapped the orange ring down a little bit since it looked like it was up too far. The next time I started my car, no check engine light! Don't know if it will work for everyone, but it's free to check it out to see if it works.

Thank you, BNaylor, I never would have checked the PCV valve if it wouldn't have been for one of your posts and I'm very grateful that you take the time to post as much as you do!