Is there any fuse for the IACV power

HASSAN SHUAIBU

MEMBER
1995 HONDA ACCORD
2.7L
V6
FWD
AUTOMATIC
156,000 MILES

About the IAC that is not getting power, does the power line from the IAC after the junction connection leads to the fuse box? And is there any fuse that controls the IAC power, because sometimes back, an auto electronic the some work under the fuse box to connect a relay That brightens my car headlights. The fuse box is the one in the hood.

4 Replies

CARADIODOC

MECHANIC
33,867 POSTS

There is no fuse for that circuit, and no power or ground wires. The IAC motor has four internal coils of wire that are pulsed with varying polarities and voltages by the engine computer, only when an adjustment in idle speed is needed. When idle speed is okay, there are no voltages applied to the motor.

A typical condition is when you shift into gear, then, idle speed drops a little. The computer sees that, then pulses the IAC motor to adjust the valve just enough to bring idle speed back up. Once that is done, there is again, no voltage applied to the motor.

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Saturday, December 24th, 2016 AT 12:48 PM

STEVE W.

MECHANIC
13,419 POSTS

On that Honda the IAC uses a bias voltage and a PWM ground to pulse a solenoid. It is a bit primitive compared to the newer systems. It pulls power from the resistor pack for the injectors along with the EVAP purge and the injector relay.

No fuse as it comes directly from the ECM.

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Saturday, December 24th, 2016 AT 3:33 PM

HASSAN SHUAIBU

MEMBER
40 POSTS

Thanks Mr Steve. But please sorry to further bother you. I want to be careful what I will do. Please assuming I got through to the ECU to check the iac power line there, if the fault is from there what am I likely to see that may be the cause and what step should I take to rectify it? Furthermore, I noticed a junction where many wires from the hood are joined to others coming from the dash. The IAC wire is among them. Is it possible to have fault there? And the connection I did from evap solenoid to iac valve, is the IAC valve opened continuously?

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Saturday, December 24th, 2016 AT 9:43 PM

STEVE W.

MECHANIC
13,419 POSTS

There is a control wire that comes from the ECU (black wire with a blue trace) it provides a pulsed ground signal that controls the IAC. With an oscilloscope you could watch the signal, but it is not something a meter or test light will show.
That junction you found at the dash is the one I mentioned above, it feeds power to the IAC, EVAP, Injector feed, and the main injector relay. You mentioned earlier that you had no power to the IAC. The problem is in the wire from the junction you found to the IAC valve.
That was why I suggested the jumper to get the IAC power again, they both receive the same bias voltage from that junction.
Unless it is faulty it won't be open continuously.

Here is a video showing the valve.
https://www.youtube.com/watch?v=aHHhRDTVWbo

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Sunday, December 25th, 2016 AT 6:07 AM