thefranks5

Got a po505 code on my 2001 Maxima.

Had a mechanic at parts store advise me not to replace the valve, but to simply clean it. He said that cleaning the valve solves the problem about 95% of the time, in his experience.

So, here's my question. I've run through several videos and strings, some have suggested cleaning, some replace. Is it advisable to just clean the Idle Control Valve and see if that is sufficient?

Thanks in advance for comments from experienced mechanics.

cornholio

iTrader: (1)

i'm not an experienced mechanic but i did go through a bad iacv recently. my vote is replace it with oem and move on with your life

CustomLowz

iTrader: (14)

If you cannot decide on what to do, I would suggest to clean it first. If that helps, great you're done. If it doesn't help, then replace it.

cornholio

iTrader: (1)

i also want to add it would be worthwhile to pull out your ecm and check for shorts (you may need to buy a small 90 degree screwdriver). 5th gen iacv is known to short ecm in some failures. hopefully this isn't your case

there's a good series of youtube videos on this- maybe 5 or 6 parts just google "youtube maxima p0505" and i'm sure you'll find it. good luck

ManualMaxima

iTrader: (10)

Cleaning IACV? I'm sure Mr. Mechanic threw that advise out, but didn't tell you how to accomplish it. I say that, because I have no idea how one would go about cleaning the IACV to make any difference. Disregard that crap piece of advise and replace it. Also as others said check that ECM, as a new IACV will get trashed immediately if the ECM which is driving it is also bad. The best point of reference is the many threads on this subject found on this site, every piece of info needed regarding a p0505 is found here. Ask me how I know? Best of luck to you...

thefranks5

Thanks for the above insights.

I believe the mechanic was saying to clean the throttle body and adjoining parts... Did that, also replaced a bank 2 sensor 2 downstream o2 sensor that threw and error code. Cleaned all the parts in the throttle body and adjoining assembly... FILTHY ... and replaced all the gaskets, reassembled.

After disconnecting the front electronic motor mount cable, I gave it a try and started the car, I found it was still idling high -- 1200-1500 rpm.

Been through the six-part youtube series with "Ray." Overall pretty good... HORRIBLE videography... nearly gives you motion sickness ... but good information.

Now, having looked at numerous other posts on the topic, about to tackle taking out the ECU to see if any circuit boards are burned. (Nothing has smelled burned so far, thank you Lord!)

Meanwhile, also looking for a solution for resetting the idle and ECU... To that end -- I found this on the Nissan forum, and thought I would share it.


"I've noticed my car won't reset the ECU by disconnecting the battery for a few minutes - but there is a way you can reset it (without disconnecting anything).

"To the right of your accelerator panel is a plastic panel. Behind this panel is your ECU. And behind a piece of clear plastic, almost like a piece of tape, on the side of the ECU, is a flathead screw.

"If you turn on the ignition (without starting the car), then turn the screw clockwise as far as it'll go, wait 2 seconds, then turn it fully counterclockwise, you've entered diagnostic mode, and the service engine light will begin blinking the stored codes. If you turn it clockwise, wait 2 seconds, then counterclockwise again, then shut off the ignition, you've reset the ECU. I'll take a picture of where it is in a few minutes."

Here's the link to that with a photo http://www.nissanclub.com/forums/gen...placement.html

OK... enough typing... on to the ECU.

DennisMik

iTrader: (2)

That info about a screw on the ECU does not apply to your car. Starting with the 2000 model year, the screw was no longer used. The thread was for an Altima and they are not always the same as a Maxima.

thefranks5

OK...Here's the update. I did clean the throttle body and all adjoining parts, and tested the system and the idle was still acting quirky... 1500-2000 rpm.

Pulled the computer as suggested, and sure enough, there was that wonderful burned electrical component smell.

Opened up the box, and compared it to a map of the motherboard. it was the IAC module.

So, needed to replace both the IAC and the computer motherboard. Online the motherboard rebuilders who have a decent reputation cost about $200, plus shipping.

God was kind, I found one in an incoming Maxima 2001 at Spalding Wrecking in Spokane. I had to wait a couple days for them to test the engine and system before they parted it out. But, worth the wait. $200, tested and with a 90 day warranty. Also bought the iac for $88. Couldn't buy just the IAC, though, had to buy the entire IAC and throttle body and butterfly valve controller.

Quick tip. instead of a 90 degree screw driver to take out the computer ECM, pick up an 8 mm box end ratcheting wrench. I got a complete set at Harbor Freight -- 8mm to 22mm for about $12. These babies have come in soooo handy on so many occasions it's amazing. Well worth the investment just for this job. I guarantee, you'll thank yourself in the long run, over and over.

I go in Monday a.m. to the local Nissan dealer and have them reset the computer for $105+ tax.

Obviously overpriced, but a necessity.

Thanks to all for the above insights. If anything goes sideways with the Nissan dealer, I'll check back in. Going to a dealer always makes me reeeeeeally nervous. Never had a single good experience with a dealership... ever.

Hey everyone, take the rest of the weekend off!

cornholio

iTrader: (1)

you wont thank yourself if you have philips screws without hex heads like 2000 and older model years. just throwing that out there for someone else who might read your quick tip.

congrats on the fix though, hope all works out at the dealer on monday

ManualMaxima

iTrader: (10)

First thx for posting the solution to your problem, I wish everyone did. Second, glad your back on the road and all is well. I went through this IACV and ECU nightmare myself once, glad I could help.