Hi guys Im new to the group, I often browsed and seen alot of great helpful hints and tips that have helped me out here so thanks much for that. So heres my story...01 MAXIMA A/T... several years ago I got the dreaded P0505 error. I replaced the IAC from pep boys and there was no change at the time. Car ran descent but needed a lil gas to get her goin in the morn but drove great once warmed up. I had passed emissions as the CEL had been intermitant. So Id rush to the inspection station before it came back on and pass. But now its constant. So I sent out ECM for repair and bench test, warranteed out IAC for new one, purchased OEM TPS, disabled the motor mounts by unplug at harness. So I removed and cleaned throttle body (bare), installed the new IAC, installed and calibrated TPS, installed reworked ECM, did the manual relearn process (not consultII). The car runs great now, idles at about 9 and drops to about 7 in drive which I know is a lil off but starts right up, I hear the IAC kick in on start then die down after warmed up, IAC steps up idle to keep level rpm as AC being turned on. Drives great, great throttle response, no bog, no surge, but that damn CEL light keeps comin on P0505. I called the ECM guys and they said they bench test the ECM and have done thousands, they have like a 99.5% rep as well so I believe them at least a lil, they tell me that I should of used new OEM IAC and that aftermarket IACs have a bad rep for creating issues like mine. What do you guys think? Is a nissan consult II relearn the missing piece as Ive seen some say its mandatory on this car? ECM complete reprogram? Should I get the Hitachi IAC? For the relearn I disconnected battery for hour or so then did the process of on/off then run and disco/reconnect TPS within 5 sec, but I read it could take up to 24 hours to erase the stored learned idle data? Does that sound right? Any help is greatly appreciated, at this point I wouldnt mind shootin anybody who helps me resolve this issue some bread via Paypal, Im at a loss, Thanks guys

 

I see first that you did the IACV first before changing the ecu. Maybe the bad ECU damaged the new iacv?

. I would try first an OEM iacv which retails for about $200. Quirk Nissan dealer has them at a fair price:

http://www.ebay.com/itm/2000-2001-Nissan-Maxima-3-0-IACV-Valve-Air-Control-Replacement-GENUINE-OEM-NEW-/321146151135?hash=item4ac5cd60df&vxp=mtr
And reopen up back the ECu and see if the chip burned again.

 

I replaced it earlier on but was under the impression that it was not a good idea to do one without the other, so I warranteed out the part so new IAC and repaired ECM

 

But thats kinda what I was thinking, Hitachi IAC And send in ECM for bench test just to verify and try again, if that dont get me anywhere, looking like stealership here I come

 

Buy the OEM IACV from a nissan dealer ..not the hitachi ebay ones...

 

changing the ecu and getting other work done to this car won't take care of the iacv, or relearn issues. the dealer has to get the relearn done.

 

i thought 00-01 relearn is as easy as disconnecting the battery for some time?

 

Thats what Im about to do because the people who rework the ECU asked about that and said it is a common issue when people use aftermarket IAC. So gonna buy OEM IAC and send in ECU to bench test then reinstall it all

 

That was a huge question of mine because I had performed manual relearn by on/off, on and let run til certain conditions, then unplug/plug TPS within 5 seconds, that process which from what some have said is all that is required. like I said the car runs great, just after systems ready CEL comes back on. I read that on certain cars the dealer has to perform relearn? Could that be all it is? Anybody gone thru this situation?

 

Yeah for sure gonna make sure is true OEM because they advertise on EBAY "OEM HITACHI IAC" but when you look at "brand" it says WD Express, what kinda misrepresentation is that? I checked courtesy parts and they claim to be on backorder on their page but found others that are legit OEM. Lookin at like $250 for it, have any of you had bad experiences using aftermarket IAC,TPS, or other sensor related swaps where all you had to do was put OEM parts and problem solved, think that a great discussion

 

Yeah Quirk looks legit, thanks

 

yea, Quirk is a large nissan dealer in Massachussets. You see a lot of cars on the east coast with Quirk stickers on the back of them.

 

I get people all the time coming up to the counter after buying one of the IAC's off ebay or AutoZone, Advanced, etc and then buying an OEM one and THEN realizing there's not a big price difference in the first place.

 

thats real talk, I paid like 225 for the aftermarket one at pep boys, have you seen where if people have switched out the aftermarket one for OEM that gets rid of P0505?

 

The car will 00/01 will work if you reset the ecu or disconnect the Battery, if it comes back the ecu or the iacv went south it usually happeneds when the parts fail or if the iacv was cleaned out or was manually adjusted. The point here is you can have the aftermarket part on and that might be a 50/50 fix because if it being and cheap or aftermarket part. Oem is always guaranteed and the part is better made to work better. The code comes back after all of the performed work the relearned Will be needed to be done, in some rare cases it can be the harness or the relay or fuse, thats rarely.

 

I See it all the time.. I fixed many many p0505's. I've seen aftermarket IAC preventing the inspection monitors to pass.

 

I checked IAC for power at harness and was good, also checked wires to see if burned at IAC and ECU, is there a relay or fuse for IAC I should check?

 

I have put a document together for people like you. Here: https://drive.google.com/file/d/0B6O...ew?usp=sharing . Read it - you'll understand the issues better.

Re. your question about P0505: Yes, it may take a while to get rid of it. The system has to go through a "full cycle" to get rid of it. Alternately, you can disconnect your battery overnight and that should eliminate the light. If it comes back however, you have a real problem.

Re. idle re-learn: No, you don't have to do one. I never did. Just disconnect the battery overnight and the car will re-learn on its own.

Re. your non-OEM IACV: Did you measure its resistance? Was it 22 Ohms? If not, then that's why you are having these problems.

 

thanks, yeah I should have measured it preinstall, Ive been reading the FSM manual, Im gonna go thru all those steps and see what happens, biggest one being tracking down those circuits and doin continuity checks, then send ECU back for bench test and install OEM IAC, then after that Im gonna bend over and let the dealer have at it, lol

 

Hi im new here and I am having the same problem. I just replaced the ECM and the IACV and a new mobilizer that is programmed to the new ECM the car will crank but not start...please help...

 

Did you replaced both your IACV and your ECU at the same time? Hope you did (see the doc above for details .... and check your fuses; also, replace fuse #58/15A with a 7.5A fuse).

Is the security light ON when you crank? If so, your car is immobilized.

Does the fuel pump run? It should run for about 2 seconds when you start cranking. Remove the back seat cushion and have a helper listen.

Do the spark plugs fire? Pull one out and confirm.

If none of the above, it's either your CPS (crankshaft Position Sensor) or your IACV (or perhaps your ECU if it got damaged again).

 

i replaced at the same time...the security light is on when i try n crank it..how do I fix the immobilizer?
which fuse is #58? fuel pump is working.

 

Sorry for just now responding to this but to answer your question, I've had people come buy an OEM from me and I never see them again. So I'm assuming it gets rid of it by that theory lol.

 

I just replaced my iacv, ecm and mobilizer w key programmed with the new ecm but car wont start and im getting solid red light when trying to start..please help

 

If the security light is ON, NATS is preventing your car from being started. I suspect you did not have your keys properly re-programmed after you replaced your ECU. If this is indeed the case, the answer is simple: you have to tell your new ECU/NATS about your old keys. This is called "re-programming the keys". Unfortunately, the re-programming can only be done by the dealer, or by a qualified locksmith. I think they charge about $100-150 for it, but you better ask.

 

no it came w a key that is programmed to the new ecm

 

Are there any steps they need to be done after installing all this?

 

Make sure you only have one key - the right key - on your key-ring when starting the car.

At any rate, if the security light is ON, it's a NATS issue (NATS = "Nissan Security System" = Nissan Imobilizer). NATS does not like your key, and it thinks somebody is trying to steal your car.

 

how do I fix this issue?

 

reprogram the keys

 

+1 !!!

 

So your saying i would have to get it towed? No other option?

 

Yes, that's the bummer. Unless you can find a locksmith that would come and reprogram your keys at your place. It's worth a try.

 

i've read locksmiths can do it

 

also curious, what did you replace?

2 things - ecm and iacv?
or 3 things - ecm, iacv, and immobilizer?

 

An independent locksmith will come out to your car and re-program the key for you. House calls cost more, but it is probably cheaper than a tow. Call around and see who will give you the best price.

Have your old keys programmed in at the same time so you have a spare in case you lose one.

 

That's 100 bucks JUST for showing up. It'll end up being about the same if they charge for the program as a tow (assuming he's within 100 bucks distance) plus half hour of labor from dealer.

Better off just buying data scan II and doing it yourself

 

https://maxima.org/forums/5th-genera...ey-reprog.html

 

yes i am going through the exact same thing....very frustrating

 

YES I REPLACED ALL THREE