High Idle Problem Remains...

[93corolla5speed]

Well, the 02 Corolla went to the shop on Thursday for the high idle problem that I bought it with. The shop said it was the idle air control solenoid, and replaced it. When I drove home, the idle was still high.

So far, the throttle body has been cleaned, so has the PCV. And, of course, the IAC solenoid. Still have the high idle, still no check engine light.

The idle is low when cold, high when hot (~1500 rpm). It's obviously a computer-related issue because when the engine is revved, it will come down to normal idle for a second then speed itself back up to around ~1500 rpm.

What else could it be????

I called the shop and its going back in on Monday. They still believe it is a IAC solenoid problem, because that is what showed up on the scan tool. I figured that would throw a check engine light, but it didn't.

[REN69]

hmmm.. it almost sounds like it's plugged in backwards.. I remember someone having a similar problem with their car, can't remember how they fixed it though.

[93corolla5speed]

Do you think that it could be the coolant temperature sensor? Even though the scan tool, according to the shop, identified the IAC solenoid as the problem?

Where is the IAC located and how can I tell if it is in backwards? If I can fix it myself, it would save me a trip to the shop tomorrow (35 mile drive!)

Thanks

[Flashmn]

as far as I know the idle solenoid is a stepper motor, with a plus and minus leads, when you reverse them they operate the opposite. I'm not 100% sure but I think this is the case.

[93corolla5speed]

Can you tell me where the IAC solenoid is located on an '02 Corolla?

[Flashmn]

no idea, manifold probably.

[93corolla5speed]

Can anybody else tell me where the IAC is located???

I want to check to see if the idiots...err...I mean, the mechanics, put the leads on backwards and that is what is causing my hot high idle problem.

Anything else you can tell me about the IAC, I would appreciate...

[Flashmn]

it should be a one way plug tho