P0507 and IAC Valve

[smetzger]

So, I am pulling a P0507 - Idle Control System RPM: Higher than Expected.

One thing I am reading is to check the IAC Valve.
When I check the resistance across the leads I am getting an open circuit. Temp is about 55F in the garage.

Its a fairly expensive valve, so I want to make sure I am not buying a $170-$200 part that is not needed.

Any other way to test, just to make sure?

Car seems to run fine, revs a little high on a cold start but once warms up idles at about 800-900.

Thanks

[smetzger]

Never mind. I was measuring resistance at the wrong terminals. The IAC valve is on top of the throttle body.
Mine checks out.

But the throttle body is filthy, stuck on black stuff, and the gasket was brittle and fell apart when I took it off.

Hopefully a good cleaning and new gasket will solve my 507 woes.

[smetzger]

Update...

1) Can't find any vacuum leaks
2) IAC valve resistance checks out ok (between 7.7 and 9.3 ohms) - but it was colder than the 73F
3) Cleaned TB
4) Accelerator cable is taught, but the TB goes all the way closed when idling

After cleaning the TB the pending 507 went away, but then CEL came back on and code was a P0507 after a couple hundred miles.
Car seems to run ok, however, cold start revs to 2000rpm until fully warmed up then drops to 800 ish.

Could it still be the IAC? How can I check the IAC when its 45F? Is it possible its the timing belt?

[smetzger]

Solved - it was the battery of all things