No power in IAC valve

HASSAN SHUAIBU

MEMBER
1995 HONDA ACCORD
2.7L
V6
FWD
AUTOMATIC
158,000 MILES

I do not have power going into my IACV. I tap power from evap solenoid as a temporary measure. But the closing and opening of the valve is not controlled. So please can someone direct me what to expect and do when I open the ECU? I have checked all the connectors of the IACV and they are In good other. And is there something else I can check before going to the ECU? Because the ECU is a delicate device.

Wednesday, December 28th, 2016 AT 10:34 PM

3 Replies

STEVE W.

MECHANIC
13,961 POSTS

If the valve is not being controlled by the ECU then the ECU has failed, It is not repairable.

That IAC does not step open and stay open on that valve design, it is a pulsed ground signal that controls it. You can test the valve by making sure it has power to one side, connect a wire to the other terminal and tap the wire on a good ground, you should be able to hear the valve move.
That engine also has a second high idle control, that is a mechanical unit with a wax pellet inside. If it has failed open the other valve may not be able to control the idle.

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Wednesday, December 28th, 2016 AT 10:58 PM

HASSAN SHUAIBU

MEMBER
40 POSTS

Please Mr Steve help me out here. I tapped current from evap solenoid with a jumper wire to the iac power line. But I don't know if the iac is functioning the way it is supposed to with this connection? Meaning if the opening and closing of the valve is controlled by the ECU. And am still not sure if the power problem is from the ECU. Please what are the areas am suppose to check before I conclude on the ECU. Thanks

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Friday, December 30th, 2016 AT 8:00 AM

STEVE W.

MECHANIC
13,961 POSTS

If it isn't idling and you don't feel/hear anything at the IAC, Replace the IAC first it's a LOT cheaper. Testing the IACs actual response on the engine without a scan tool is almost impossible because you can't tell what percentage it is being opened, so the pulse train from the ECU is useless. This is one of those times a shop has the proper tools. Unless you have a scan tool that has bi-directional control and can talk to the ECU.

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Friday, December 30th, 2016 AT 2:31 PM