The Idle Air Control valve is a complicated mechanism that opens to allow air into your intake manifold without the use of your throttle body. Your Honda Accord ECU controls the engine idle by activating the idle air control valve into action. As the engine and combustion chambers need it, this valve opens to allow unmetered air to enter the engine.
OBDII DTC P0505 is a trouble code that’s very common in the Honda Accord. Today’s test vehicle is a 1999 Honda Accord EX with the 2.4 liter SOHC F23 VTEC engine. Today I’ll be showing you How To Replace Idle Air Control Valve in your Honda Accord. If you have not already done so, try adjusting your idle screw or clearing your OBDII check engine code by using a scan tool.
The specific verbiage for the DTC P0505 is Idle Air Control (IAC) Malfunction. We’ll be replacing the IAC in your SOHC 2.3 liter F23 VTEC engine, and showing you how to do this in a 1999 Honda Accord.
The part number for this Honda Accord IAC is 36460-PAA-L21 and most replacement units come with the three way idle air control valve gasket.
Symptoms of DTC P0505
- Hard to start engine
- Irregular idle
- Bad performance
The Idle Air Control Valve is a stepper motor that uses coolant to quiet it’s operation. Because of this, you will need to check several coolant ports and disconnect them. Part of our how to replace idle air control valve DIY guide is disconnecting these coolant lines, and removing the IAC.
If you are working on the same vehicle we are, you know how tight of a fit this can be. Try to keep your tool selection to open ended, smaller 10mm ratches to help you get this job done.
Before you begin our how to replace the idle air control valve in your Honda Accord DIY Guide, disconnect the negative terminal on your battery. Now open your hood and locate both your manifold absolute pressure sensor (MAP) and your throttle position sensor (TPS) and disconnect both.
There’s two coolant hoses that are clamped onto the bottom two nipples, and one goes to the coolant passages from your throttle body. The other coolant hose leads to the back of your Honda Accord engine and connects to the water pipe.
The last hose leads to the intake tract, and it’s the source of your IAC air. Do not mix up these hoses, or you’ll be flooding your engine with coolant. For best results, leave these hoses on until the last step.
Remove the 10mm bolts that hold your Honda Accord Idle Air Control Valve to the back of your F23 intake manifold.
Remove your idle air control valve, and clean the back of your intake manifold.
If your old idle air control valve gasket is still stuck on the intake manifold, remove and discard. After cleaning your mounting surface, take your new Honda idle air control valve and carefully transfer over the hoses. Do not mix up these hoses and make sure that the vacuum hose is the top most one out of the trio of nipples coming out of your IAC.
Once you have transferred over the hoses and done it one hose at a time, insert the new idle air control gasket. Honda does not call for gasket maker here, carefully mount the new unit with new gasket and tighten the 10mm bolts to complete our guide.
Using a scan tool, erase your OBDII DTC P0505 and go on a test drive to see if this condition returns. Once you’ve replaced the idle air control valve and installed it, you have fixed your DTC P0505 for Idle Air Control Valve Malfunction. Have a question about our DIY guide on How To Replace Idle Air Control Valve? Leave us a message below!
I have a 2000 honda accord 4 cylinder and it’s hard to get too so I need help on how to get it off and to replace it
Hi Tommy, thanks for reading.
Yeah there’s no real easy way to go about it other than we recommend a slimline ratcheting 10mm wrench to remove the gasket. It’s no doubt a very difficult job because it’s so close to your firewall.
Sorry to be the bearer of bad news. Let us know how it turns out and good luck. Thanks for commenting!
Hi I have a 1999 accord 2.3 vtec my car runs really good but if I step on the gas all the way it lags for a couple of seconds and then it takes off could the aicv be the cause of it and also if it’s on park and I step on the accelerator and let go of it it dies out
Hi Omar, thanks for reading.. Yes it does sound like IAC could be the culprit.. Try disconnecting the coolant lines that run to it and listen to the valve. It should be buzzing during operation, which means it’a at least trying to do something. If you hear no buzzing or it’s a loud grinding instead there’s something wrong with the idle control valve itself.
Thanks for commenting! Let us know how it turns out!
Hello there. I am the owner of a 1998 Honda Accord ex 2.3 vtec sedan that has been the bane of my existence, but that is another very long story. Two (2) mechanics have suggested the IAC valve because during warm up, it starts out at about 1400-1500 rpms. As it gets closer to 1000 rpms, it starts to idle really rough for a few seconds then on it’s own it acts as if I gunned the engine and smooths out ready to go. If I start driving before the “vroom”, it jerks for a few minutes while in motion as if it is starving for fuel. Any suggestions. The lowest I can get a new IAC installed for is $470.00.
Hi my 99 Honda accord the idler goes up and down do you think it’s the iac problem
Hi Hugo, before you check your Accord Idle Air control valve, check for air leaks in your intake pipe!