service engine code

[OneNice97RS]

I pulled a service engine code last night off my 97 A4 and got 2 identical "auxillary emission control" codes....Cat. is fine i think, so I was thinking O2 sensor...but a mechanic neighbor said a vacuum line or something like that...Any ideas as to what it could be???

[98Camaro3.8]

That's usually the EVAP system, but we need the actual code number to know what the problem is.

[OneNice97RS]

i believe it was a p1406

[98Camaro3.8]

DTC P1406 Exhaust Gas Recirculation (EGR) Position Sensor Performance

The EGR valve is not operating correctly. It could have some carbon buildup that is causing the valve to stick, or there could be an electrical problem with the wiring to the valve.

Without a good scanner to read the commanded and actual positions, the first step would be to make sure the EGR valve is plugged in correctly. Then you might try removing the valve and cleaning it out. If that doesn't work, replace the valve.

Could also be a bad fuse, but I'm not sure exactly which one it is. Either check them all, or let me look it up later.

[OneNice97RS]

I remember the scanner saying something like "auxillary emission control" or something....code could have possibly been a p1404 but that would have been it.

[98Camaro3.8]

"Auxillary emission control" includes things that aren't part of the standard OBD-II error codes. That includes some EGR and EVAP codes. EGR is one of those auxillary emission control systems. ;)

[OneNice97RS]

havent replaced it in a while....will probably change out and disconnect batter to reset codes...hopefully thats the culprit.