What is iacv - Civic Honda Cars & Trucks

With a scanner, you can open and close the IACV. Most times it is just dirty. Remove it from the throttle body. use brake clean and soft brush to clean most of it. The n open it up and use a tooth pick or paperclip to clean the inside.

P0505 - Idle Control System Malfunctionhttp://engine-codes.com/p0505.htmlForum CodePossible causes- IACV-AAC valve harness is open or shorted
- IACV-AAC valve poor electrical connection
- Faulty IACV-AAC valve

Read more: http://engine-codes.com/p0505.html#ixzz1zVJIt34L

Hello and welcome to FixYa!
This can be caused by a faulty IACV (idle air control valve). If the IACV is faulty the engine can misfire or can cause stalling. The IACV is located on the throttle body. You may need to just clean it for the strainer can be full of dirt. If cleaning doesn't resolve it then you may need to have it replaced.
Hope this helps and thank you for using FixYa! Have a good one!

Hello and welcome to FixYa!
Looks like that you have a failing IACV (idle air control valve). If the IACV is faulty, the vehicle tends not to start or may stall during operation. I suggest that you have the vehicle scanned to know exactly what the fault is. Though I suspect that it's the IACV.
Hope this helps and thank you for using FixYa! Have a good one!

Hello and welcome to FixYa!

Try to check the IACV (idle air control valve). If the IACV is clogged with dirt you'll have vacuum irregularities, one good reason why the idle is below 500. If cleaned and problem still persists, then I suggest that you replace the IACV itself for it can be faulty.

Hope this helps and thank you for using FixYa! Have a good one!

Disconnect the iacv and if the idling performance doesn't change from what you are experiencing then it may not be turning or the passageways are clogged and need to be sprayed out with cleaner.

One can test the continuity of the iacv to see if it is within specifications using a multimeter.

One can turn the a/c on and if the car stalls, then the iacv may not be working.

Good luck on this diagnosis.

You probably have a bad Idle Air Control Valve (IACV). If it does not control the idle correctly , you can find yourself driving 50 MPH with out touching the gas pedal. The IACV is located on the throttle control valve and is typically held on by two or three small screws. The price for an IACV can run from $25 to $500. I purchased a throttle body for $40 , removed the IACV, and saved $400.

The surging is related to your Idle Air Control Valve (IACV), it adjusts idle based on coolant temperature, your coolant could be low or your IACV could be bad.

Hey Jruthesq

The 850 is equipped with an Idle Air Control Valve (IACV) which supplies the engine with air when idleing (a necessity since the main throttle body valve is completely closed when no throttle is applied, thus the engine would lack air without the IACV when idleing). The IACV is suspended in a rubber mount on the front of the throttle body itself, and is easily removed and inspected/cleaned. If it's dead a good cleaning usually gets it going again. Also make sure that the air from the IACV is unhindered on its way from the IACV to the throttle body (it's actually common for the holes in the throttle body to be gunked up so bad by hardened carbon deposits that one sometimes needs a nail or even a drill to open it up again).

Just thought I'd mention this since you said that the gas needs to be feathered for the engine to start. When you press down on the gas the main valve in the throttle body opens up, closing the IACV and supplying the engine with enough air.

Oh and if your fuel pump relay is a green one marked 103 you should replace it with the new and improved red one. The relay is located under the fuse box cover under the hood. Remove the 4 torx srews holding the cover in place and you'll see the relays under there.

Good luck mate!