Error Code P0505 - ICV

[mblenis]

I have the error code P0505. Prior postings seem to indicate it is the Idle Control Valve. However, I am unclear when looking at pictrures, it appears there is a "black box" with some type of "flutter valve" that is in front of the ICV. Is this the case? I also get the error codes P0171 and P0174, which talk about Bank 1 and then Bank 2 being to lean. What are Bank 1 and Bank 2?

[lo_jack]

From what I remember when I did this, there is a little metal cylinder under that black box, under the manifold, that controls the amount of air going to the engine at idle, since the throttlebody apparently is open 0% at idle. It plugs inline with the secondary air hose coming off the primary air inlet into the throttlebody if I remember correctly. I think it is held to the underside of the manifold partially by a rubber band. Again I vaguely remember this process, but it is not overly difficult. You need to pull of most of the intake system from the filterbox to the throttlebody and set it aside to gain access to the ICV.

Your lean codes are probably the ones that say the engine is way to lean at idle. Bank 1 and 2 refer to the set of cylinders the oxygen sensors are monitoring.

When the ICV craps out, it can die in one of two ways: Not enough air gets to the engine at idle, or too much gets in at idle. Yours seems to be the latter.

When too much air gets in, the computer adds fuel to compensate, until it reaches the limit of that band aid fix. The idle is horrible and your fuel economy is probably garbage also.

In general, too much air and not enough fuel = lean and hot, engine could go boom. Not enough air and too much fuel = rich and cold, not likely to run, could wash out the spark, etc. Because this is just your idle, it is not likely to cause a lot of damage, but it is going to have a hard time idling and you will waste fuel.

If you replace the ICV, reset the computer and allow it to learn and adapt the idle fueling process to non-malfunctioning equipment, it should run fine. My ICV stuck open, so my computer added fuel until it could no longer add fuel to idle, and the idle got bad and my fuel economy went to hell.

[mblenis]

Great information, how do you reset the computer. It does look like I should replace both the "adjuster" and the ICV. Does that make sense?

[lo_jack]

Unplug the battery and let the car sit for a while. I don't remember how long it takes though, but eventually the computers memory clears and it will have to relearn next time you drive it. Yeah if I had to do the ICV I would do them both while I was in there.