Newbie on ECU code

Hi, I'm new here and really excited after finding this forum.

I have a question, and hopefully can get some help here. Thanks.

My 95 Sentra GLE check engine light is on, and AutoZone pulled a code of P0400 - EGR mulfunction. I looked at sentra.net, and for my car the code should be two digits; even after I checked codes for 96 or newer, I could not find 0400. Could somebody shine some lights here?

The gentleman at AutoZone was really nice, and explained to me it could be (1) Gas gasket leaks (2) EGR valve problem (3) Idle air valve problem. He sort of eliminated (1) after checking it out, and suggested (3) is likely after I told him my engine could not maintain idle speed and might shut off at traffic lights if the A/C is on. I wonder if anybody here has more experience on this. If it is (3), is a repair neccessary even if I don't use A/C?

Thanks again,
Bo

[nissannut]

Those are good places too start. I would start loking at the EGR first. But it may not be EGR thas is bad...

I am not sure on 95 sentras if EGR is controlled (opened) by vacumm or some electronic switch.

EGRs are opened by vacumn pressure or the ECU to recirculate exhaust fumes back into the intake to be reburned, thus saving the enviroment.. You may have a STUCK open egr. This would make a big leak at idle.

EGR should not be open when cold or at idle thats why they are controlled by water temp and or ecu.

Does this make anysense??

You can remove and clean out carbon deposits and reinstall. Worst case you may hav too replace the EGR valve.

Are you familiar with EGR valves? its the thing on the intake with a metal tube thats connected to the exhaust.

Appraciated it. nissannut.

I will definitely look into EGR first. What if it's IAC valve?

Would that be bad?

[nissannut]

I think thats the name of the valve the increases the idle when the AC turned ON. This is so the engine load will not kill the engine..

I would start with th egr due to the error code..