Hi everyone, my 2003 accord ex-l v6 gets the P0506 and idle rpm drops to 500 and drives rough just about everytime my engine is running hot and i'm running the air conditioner.
When this occurs, I sometimes turn off the AC if it's not unbearably hot outside and it would drive more normally and the engine light goes away after a bit of driving. This keeps happening over and over ever since this summer or when the weather gets hotter than 80 degrees.

I tried searching around and most results just says to clean the throttle body so I am hoping anyone here might be able to know what is causing the CEL.
I've already changed the engine air filter recently and cleaned the throttle body some time last year, in which it didn't look dirty to begin with so that might not be the issue?
Any help is appreciated, thanks in advance.

Edit: just remembered, when the CEL is on, my AC blows warm air while moving slow until I start driving 30mph+. Also sometimes when the engine light is not on, my rpm fluctuates between 550-650 when I have the AC on. Could there be a problem with my HVAC system that's causing the P0506 code?

 

How high does the temperature gauge get when this happens? There's no numbers on it so just estimate like 50% is the middle line or 100% is all the way to the top.

Does the radiator fan run when the engine temperature gets high?

P0506 is for the idle-control system ("idle too low") which might mean the IACV being dirty, plugged, or not working right.

But as far as the AC system being the cause, have you done ANYTHING with the AC system? Had to recharge the refrigerant? Maybe the compressor beginning to have problems causing excessive drag on the engine?

 

Temperature gauge is about 50% like all other cars, it never got higher than that. Radiator fan runs about 80% of the time or so?
I didn't do anything with my AC system but I did recharge my own refrigerant with A/C Pro like 1.5 years ago. The AC actually cools fine until the P0506 kicks on

 

When you get this error you would check your throttle body and a/c.

How many miles do you have. Have you ever replaced you PCV? Have you checked for vacuum leaks?

After checking for leaks clean TB and iavc. Once clean do an idle relearn and clear the code. I've had this issue and cleared it with is and replacing the pcv. My pcv was still good though.

 

On my wife's car, the idle kept fluctuating when it was acting up. The AC being on actually help stable it. Turn off the AC, and it would bounce between 1200 and 1800 rpms (very high idle). Yours (the OP) might be the opposite of that. Make sure there's no air in the little lines, as this can cause similar issues, as the IAC needs hot coolant flowing thru it to work correctly (what causes the idle speed to drop).
I hope this helps.

 

thanks guy, i haven't had time recently but i will check and try your suggestions and see if it fixes the problem when i'm free.

 

Did you ever get resolution to this?

This is exactly my problem. CEL will pop if its warm and im idleing a lot with the AC on(ala, stop and go traffic). Then the AC doesnt really cool unless im driving.
Engine may be a little rougher but not huge difference.
CEL clears after a day and everything works great.