How do you check the IAC?

[CTroxtell]

I looked in the Haynes manual and it says on the wiring harness side I should be getting 10 to 12 volts with key on engine not running. I am getting nothing but maybe 60mV. I have got the engine to running right a time or two just by messing with it but it never fails...I get it to run right, drive it to work, cut it off and when I get back in it and start it the blasted thing don't want to stay idling and it has about gotten me run over by stalling out. I'm wondering if its not in the wiring harness or the computer.

 

[CTroxtell]

No one knows anything about the IAC? Mine appears to be getting no voltage if I tested the wiring harness right...help before I get run over by stalling out please.

 

[FIND]

Double-check what you are using for a ground when you are testing the IACV. Just ground straight to the battery when you are testing the harness.... I didn't think that it should actually be getting 10-12 volts though, I wonder if the haynes manual might be wrong, I would think that 12 volts would short the sucker out. Take the IACV off, gaskets are cheap. Clean the IACV, plug it in and observe it for operation.

 

[Iron Weasel]

Key "ON", engine "OFF".
Idle Air Control (IAC) solenoid disconnected.
Measure voltage between VPWR (red wire) circuit at the IAC solenoid vehicle harness connector and battery ground.
It should be 10.5v or higher, since yours isn't, that means there's an open in the circuit.

The IAC gets power from the same circuit as the fuel injectors, EVR solenoid, and camshaft position sensor (if equipped). If you have power to those components, then the open circuit is between the splice for the injectors and the IAC. The power for the entire circuit comes through the ECM on pins 37 & 57.

 

[FIND]

Key "ON", engine "OFF".
Idle Air Control (IAC) solenoid disconnected.
Measure voltage between VPWR (red wire) circuit at the IAC solenoid vehicle harness connector and battery ground.
It should be 10.5v or higher, since yours isn't, that means there's an open in the circuit.

The IAC gets power from the same circuit as the fuel injectors, EVR solenoid, and camshaft position sensor (if equipped). If you have power to those components, then the open circuit is between the splice for the injectors and the IAC. The power for the entire circuit comes through the ECM on pins 37 & 57.

I stand corrected I guess.....

Either way, when you are testing a circuit, use the negative post on the battery or a known good ground for your negative lead. Maybe that is all your problem is. Otherwise, it is as Iron Weasel says. Your short is not too far away.

 

[ragajungle]

Key "ON", engine "OFF".
Idle Air Control (IAC) solenoid disconnected.
Measure voltage between VPWR (red wire) circuit at the IAC solenoid vehicle harness connector and battery ground.
It should be 10.5v or higher, since yours isn't, that means there's an open in the circuit.

The IAC gets power from the same circuit as the fuel injectors, EVR solenoid, and camshaft position sensor (if equipped). If you have power to those components, then the open circuit is between the splice for the injectors and the IAC. The power for the entire circuit comes through the ECM on pins 37 & 57.

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This guy is a walking verbatim shop manual...everytime I see a wiring diagram or vac schematic it says (Iron Weasel) Thats awesome Thanks!