i have had an egr code for a while now. the dealer told me that the egr valve is working properly and that i should try replacing the egr solenoid because it might be having problems intermittently. i replaced it and reset the light, and there's no end in sight because the light just keeps coming on. i took the egr valve out and cleaned it and it seems to be ok. a new egr valve is almost $90 and its not worth it to me unless i know for sure that it will fix the light. does anyone know if anything else could throw that egr code(i think its p0400). please help.

 

The dealer should have been able to differentiate whether it is an EGR valve (P0400) problem or an EGR vacuum solenoid circuit (P0403).

Often the problem is due to inadequate flow through the EGR valve. This can be due to the passages being plugged, or due to low back pressure in the exhaust system. Your headers reduce the back-pressure in the system. Might also indicate a problem with the vacuum lines. Has the dealer checked the vacuum lines? I think there may also have been a "Techincal Service Bulletin" (TSB) dealing with this problem on the OBD-II (96/97) cars. Did the dealer check for a TSB?

 

no, the dealer did not check for a TSB. When i took the egr valve off to clean it i dont remember there being a gasket, the dealer could have forgot to put it back on or maybe its on the intake manifold and it just didnt come off. i'll have to check for it, i guess there could be a leak there then.

 

There's a graphite impregnated gasket on the EGR valve. It usually sticks to the intake manifold.

 

my car has this same problem...started right after my header install. if you figure out whats wrong with it, please let me know.