1998 Corolla Iac Valve - Toyota Corolla, Chevy Prizm (1998-2008)

So I went to Autozone and had them check the code as my check engine light is on. Just as I suspected, it is a IAC valve fault. The cost is something like $245.00 for the part. I have read that it maybe possible to clean the IAC valve and reset the check engine light. Without taking all apart, is there a way to test to see it can be cleaned or should I just go to a junk yard and pull a used one off. The only issue with the car is low idle at start up for a few seconds then everything seems to be fine. Any and all suggestions would be greatly appreciated. If this has been covered in detail elsewhere, please link me to the post.

Thanks,

Ken

Unfortunately, you have to pull it off to test the IAC valve. That point, might as well just clean it out and see if that helps any. For $245 - you could buy a couple of used throttle bodies and pull those IAC valves off.

Assuming that you checked on the usual suspects - cleaned the throttle body, no vacuum leaks, PCV verified to be in good shape, good plugs, plug wires fine, etc?

Unfortunately, you have to pull it off to test the IAC valve. That point, might as well just clean it out and see if that helps any. For $245 - you could buy a couple of used throttle bodies and pull those IAC valves off.

Assuming that you checked on the usual suspects - cleaned the throttle body, no vacuum leaks, PCV verified to be in good shape, good plugs, plug wires fine, etc?

Funny thing, Changed oil, plugs, wires and did a flush on the radiator and the CEL went off. Still rough idle for a few seconds on cold start up though. Problem solved?

Ken

Did you scan the ECM? CELs will turn themselves off after so many "cycles", but the original code will still be stored in memory.

A quick test to see if the IAC is "stuck" - kick on the A/C when the car is running. If idle speed jumps up in response to the added load - IAC valve is probably still functional, though may still need a cleaning. If the engine stumbling gets worse when the A/C is kicked on, or if the idle speed did not increase - then the valve is dead or dying, a cleaning here may or may not fix it (i.e., bad solenoid).

Probably can't hurt to run a good fuel injector cleaner to see if that improves the idle. Some ones that people have reported good luck with are Valvoline fuel system cleaner, Gumout with Regane, Chevron with Techron, and my favorite - Redline Sl-1 injector cleaner. The earlier 1ZZ-FE had injectors that were prone to clogging, and the reason why they redesigned them in the later models (2000+).