freddy

ive had p0505 light come on which ofcourse is aicv only problem i have is when cold i need to give it a lil gas other than that car runs and idles fine. ive read alot about this problem at this forum so i decided to do nothing to fix its been two years now and other than cold start all is well.so my question is am i unknowingly damageing my engine?

freddy

im a newbie soooo hears my question. ive had p0505 ses light on for two years because of all the problems associated with repairing aicv, and my only problem is that my 01 max needs a lil gas during cold start then car runs fine. am i unknowingly damaging the engine.

doublea

iTrader: (7)

Hey guys, the definition of the PO 505 is " Idle Control System Malfunction " On most case the car die on cold start if you dont give a little gas. Some say their car died every here and then, but would idle fine when the car is warm some dont, but the symptom are very similar.

Many people ended up changing the entire throttle body or just the IAC. I believe in many situation the problem still persisted and PO 505 got back shortly after, like the next day or next time they take the car. I heard some story about guys spending close to 2000$ at the dealer to have the entire TB swap, and still having the PO 505. After many trip to the dealer he ended up having to replace the ECM for another 1000$ and such.

My cousin called me yesterday to ask me if I could helpt since he's got the PO 505 for few weeks on his 2000 GLE. His mechanic has swapped the TB but the car has the same problem, when he called me I though maybe his mechanic has swapped a defective TB that he got from the junkyard.

Long story short, yesterday he stop at my house and I showed him what the TB look like, I have 3 spares, all from 5th gen, the only difference between the 2k and the others is the 2k has a vacuum tube see the first pics:



Now the only parts of the TB that can go wrong is either the IAC showed here:


or this part wich I dont know the english word for it.lol



Yesterday I replace the part showed on the last image but that didn't changed anything and the problem persist, I also erased the code yesterday but it came right back and my cousin has the same problem. His IAC valve has been replaced about 18 months ago when it was acting weirdly like shooting the rpm to 2000 and then dropping to 0
after I replaced his IAC the car was as before and be driving nice since the PO 505 showed up. I have a spare IAC valve that I know is working well, se we are going to try that last one and see if that cold start behavior can be also related to the IAC valve.

If after all what we are trying, we still have the PO 505 then I'll be convince that the ECM is the one & only culprit when PO 505 show up.

Bronzie2K

Double A. The part which you are pointing to in the last image is called a TPS (may be worng) ...or Throttle Postion Sensor. I too have a P505 code. The code came about as I was attempting to remove the entire TB. After moving several parts I decided that i wasn't going to go through with the procedure because something else might go wrong, and it kinda did. After placing most of the parts back I realized that I had misplaced 1 of the 2 screws attached to the IACV's connector. I figured I'd replace it later but I never did. The next day the IACV threw a code. Its been 4 months now and I've ignored the code. I could have easily placed the screw back but it seemed like every time I went chasing after codes the problem got worse. Strangely, my car has been great since then even though I'm sacrificing a few mpg's. My car's intial problem was that my 2k Max (GLE,a/t,110k) was experiencing hi revs when cold at idle and lots of hesitation when warm <driven for a hour+> at idle/neutral/drive. The car would just throw OS codes like rice at a wedding. After taking the car to the dealer and several mechanics, it seemed like I knew more about the problem than they did. The big time dealership claims to have diagnostic equipment specailized for Nissans but was unable to diagnose if the car had a valve leak but was quick to overprice simple procedures. I followed several FIY suggestions on here but the problem still continued. A few months back I decided to drain about 70% of my trans fluid and replace it with dealership fluid. I also made a habit of filling my tank up once every other week at a nearby Sunoco as oppsed to frequent stops at random stations. After a few weeks, no hesitation and the car ran smoothly even though codes were still present. Well, I'm due for inspection right now. I guess its back to chasing the light.

meseville

I am looking for the procedure to adjust the TP sensor on a 2000 Maxima. I did find a thread where someone asked for this exact procedure but was referred to a much older, none similar, 1993 Maxima.

theKNICKSNY

ok so my car dies on idle while in drive only

rpm's idle at 400 at warm idle and then die randomly

i get the p0505 and engine surges and jumpy idling

should i just replace the iacv or what would be an alternative?

i'm in college and cutting costs would be great.

doublea

iTrader: (7)

MY cousin still have the same problem and it's been over a year now, his mechanic kind of adjust the idle a little higher than usual and for now he stick with that, since the car run ok, but he's going to visit the dealer soon and see what's the diagnostic. I'll put a dollar on the ECM. It happen when my car was under warranty that after replacing the IAC they told me the the ECU was fried, I believe it happen 2 times but when I picked up the car it ran fine. A year or 2 after that my IAC went bad again, this time I ordered a new one and changed it myself, but I was careful to unplug the battery to make sure nothing happen with the electronic component and the car ran very well, I erased the code and it never came back.

doublea

iTrader: (7)

It sound like your IACV is gone, I believe I order it true Rock auto, at the time it was around 165$ US, but the local dealer was asking almost 600$ cdn for the IACV. Just make sure you unplug the car battery before you remove the IAC and put the new one in. Otherwise just go to the dealer and ask for a diagnostic and cost evaluation, tell them your a poor student and you need to plan your expense once they tell you what's wrong tell them you will come back when you have the cash. If it's the IACV then you knwo you can do the job yourself, then go buy it from Rock auto or a similar place and replace it your self. Unless they tell you that it's the ECM or something you cant do your self, just play the little poor student boy saying you will try to get money from your parents but you need to tell them what is wrong with the car and therefore you need to bring them a proof or something that is written. Lol

alpatnip

I've got the same problem with my 2001, but my dealer is 100 miles away. I will reinstall my original IACV, adjust it to a nice idle speed by turning the pintle manually, and live with the fault codes!

I have a new IACV valve that will be for sale soon (I'll check the resistances of the coils first). Make me an offer!!

ALP

OOmaxSE

iTrader: (19)

I have the same problem now, throwing the P0505 code and my car immediately dies on start up. When I"m lucky, it will keep a low 400 rpm idle but driving a mile down the road it will drop to zero. There were also 1500 rpm jumps. The car is far from drivable.

Funny thing is, after following P.Samson's advice about listening to the IACV from the "off" position to "on," it seems that my IACV is buzzing aka functioning. I am very curious as to why the ECM will go or short out.

Also, anyone have a working IACV available? Another poor college student here...

OOmaxSE

iTrader: (19)

I have the same problem now, throwing the P0505 code and my car immediately dies on start up. When I"m lucky, it will keep a low 400 rpm idle but driving a mile down the road it will drop to zero. There were also 1500 rpm jumps. The car is far from drivable.

Funny thing is, after following P.Samson's advice about listening to the IACV from the "off" position to "on," it seems that my IACV is buzzing aka functioning. I am very curious as to why the ECM will go or short out.

Also, anyone have a working IACV available? Another poor college student here...

btw, which fuse is #58 on the side of the battery?

doublea

iTrader: (7)

alpatnip, seem to have a IACV available, but if I were him I would keep it anyway. I dont think buying a used IACV is that much of a good idea, but look here:
http://cgi.ebay.com/ebaymotors/00-NI...051210005r2282

RiDe DaH MaX

i have spoken 2 dave b about the ecu and the iacv he told me that one of the problems is the motor mounts....the motor mounts short out the ecu and the iacv so best bet is 2 install new motor mounts or just disconnect them and then repalce the ecu n iacv

doublea

iTrader: (7)

That's kind of weird ! But I have removed the electronic part of the motor mount with the rebuild, it was full of rust down there so I took them off. I'll call Dave B in the morning to get more infos.

AA

BenRichards

Hey guys. Bumping this old thread since I can't seem to create a new one. Here's my situation, I was having the hunting idle 1500 to 2000 or so and p0505. I replaced the IACV and cleared the codes and it seems fine except now i have the hard start need to give it gas issue. Once running it will idle about 600 or so. Is that the TPS or the ECM? Or something else? Any help is greatly appreciated!

P. Samson

How long have you driven the car since replacement of the IACV? Did you accomplish the Idle Air Volume Learning procedure?

joab

I have the exact same problem.
Last year I smelled a burning in the engine and my car died. I restarted while on the road an all was fine but I noticed that I needed to give my 2001 I30 a bit of gas to warm it up a bit. The P0505 error soon followed. I ran with this IAC error for about 12 months until finally I needed to keep my foot on the gas while at a stop sign.

I replaced the IAC and now it idles at 1500 to 1700.
I checked for vacuum leaks and there were none.
Finally, I pulled out the ECU (scared to see what I would find) and the STA509A is burned up. Now I know what that burning smell was a year ago.

I ordered a STA509a for $10.99 on ebay and should receive it next week. I am going to have a friend at AMD semiconductor replace it for me next week and I will let you know how it goes. The cheapest USED ECU I could find on nationwide junk yards was $158.00 I will try the $10 chip first and see what happens.

It can't hurt to pull out the ECU and take a look, just make sure you have the battery disconnected and ground yourself. In less than an hour you should be able to pull the ECU from the side of the console behind the radio. It isn't too intimidating.