IACV crapshoot - to swap or not to swap, that is the question

gpresar · 10-06-2009, 07:07 PM

I recently replaced my MAF sensor in my 5th gen GLE (Y2000, 149K miles) and was blown away by the increased power!

Afterwards, my idle was a bit high at around 900 RPM, which isn't a surprise given the need to perform the Idle Air Volume Learning (IVAL) procedure anytime you mess with the air intake system.

My problem is that I have been unable to get IVAL procedure (non-Consult method) to work despite many attempts, careful timing, etc. - the SES light simply stays on solid.

Prior to performing IAVL I performed the Accelerator Pedal Release Position Learning and Throttle Valve Closed Position Learning procedures, checked the PCV valve, and everything else I could think of. So assuming that I haven't goofed up on the preconditions and procedure, does anybody have any suggestions about what might be going on?

I am getting an occasional P0505 code, which has me wondering if my Idle Air Control Valve (IACV) might be on the fritz. However, I hear that it appears to be doing its thing after the ignition is turned off (clicking and buzzing for a few seconds). Also, when I ohm out the pins I see a consistent 23 ohms across pins 1-2, 2-3, 4-5, 5-6, which seems to be nominal.

I'm at the point where the only thing I can think of is to swap out the IACV, but this is an expensive part and the P0505 trouble code seems to be broad enough to not point directly at this part. The cable, pins, etc. appear to be good.

I live in Seattle and am hoping to get this thing resolved before the ten-month rainy season begins!

Thanks in advance for any advice.

Gerry

AEMAXIMA01 · 10-06-2009, 07:48 PM

My 01 went crazy this past spring. Wouldn't take the idle relearn, I had tried cleaning the TB, no dice. The IACV went out and took the ECM with it. I had to pay for the IACV but the ECM was covered under the 8yr/80k emissions warranty by nissan. I'd bet it's your IACV that's the problem. Hope it didn't fry your ECM too. Good luck.

edit: I also vaguely remember getting the P0505 code, if that's worth anything.

gpresar · 10-06-2009, 08:05 PM

You've got me scared by the cooked ECU tale. Perhaps there is cause for hope in my case as none of the pins of the IACV were dead shorts, which could certainly destroy connected electronics if current limitation is not built into the circuitry. This may be why I'm reading so much about ECU and IACV dual failures. . .

AEMAXIMA01 · 10-06-2009, 08:22 PM

Yep, it happens a lot, unfortunately.

Engine Stalling

acclimate · 10-08-2009, 11:48 PM

After changing the gasket and O2 sensors my car started stalling as soon as I release the pedal. I read from Maxima.org users that its probably the IACV causing the stall and how IACV failures tend to fry the ECU. I stopped messing with the car and ordered the IACV. Autozone sells it new for $160. I got mine new off ebay for $70. I figure it sucks to replace one expensive part, but it'll suck even more to replace two of them. GL

acclimate · 10-09-2009, 12:21 AM

I was just reading about motor mounts and came across the code you mentioned.

dewd said:
"(unrelated) also folks this little thing can cause your ecu to go south as well if it decides to seize... its called a iacv...and its not always your friend!!! beware!!! beware of the p0505 code!!! unfortunately theres no solution for this but to just replace...cant prevent/unplug the iacv lol"

2000 electronic motor mounts