IAC Valve Inquiry

[RyanHilliker]

My OBD-I system is telling me code 12 - Battery disconnect (It has always done this with every code it ever tells me) and code 25 "IAC Valve short circuit or vacuum leak detected".
So why would my manual even tell me such errors without telling me how to diagnose whether it's an electrical problem or vacuum problem? Who knows.

But basically what I want to know is where can I find my IAC Valve and how I know if it's a problem with the Idle Air control valve or a vacuum (and which vacuum!?).

Any information regarding this valve or any experiences with such problems would be useful. Also, would not fixing an IAC problem damage the engine? Because I think my Neon is nearing a possible end to it's reign of immortality. It's at 191,000+KM and has been through misfires and every problem known to mankind except for a timing belt tear or anything that major.

[das2123]

Does you car run smooth, but idles like crap? If so, then it's probably the IAC sensor. This is located on your throttle body. Make sure its clean and seated correctly in its place. After you check/clean/replace the sensor, reset your PCM by pulling the fuel pump fuse from your PDC for about 10 minutes. Try the key dance and see if you get the same code again.