IACV/ECM replaced, runs great, no light but still pulling code p0505

[TheReplay]

Hey all, ive decided to post a thread to see if anyone can shed light on this.

The chain of events is as follows.

I recently replaced my IACV, however this wasnt enough as the erratic idle problem continued.

From here it was clear that my ECM was a problem too.

I pulled the ECM and replaced/repaired the damaged component. I reinstalled the ECM and voila, the idle was no longer erratic and the car idled fine.

During this time i also replaced an o2 sensor.

I cleared the codes via my DTC reader.

I went through the prpcedure for the idle air relearn, which seemed to produce a result, i.e.. this could just be my perception but it seemed like the idle went down about 50rpm from where it was prior to the idle relearn procedure.

I went on a lengthy drive to try and induce a drive cycle (need to pass emissions), so i did the coasting, accelerating, no braking thing..

I pull back into my driveway and hookup my DTC reader to see if i get a "green" emmissions light. There was NO service light illuminated so i thought i was going to be fine, however the code reader pulled codes p0505 along with p0455 and p1448.

Again no SES light illuminated.

I had to leave town that night so no fooling with it.

From there i unhooked the battery and left accessory power on hoping to drain and clear the codes via different way than just erasing them with reader. Left it that way for 24 hrs.

Had someone at the house reconnect the battery and drive the car a few miles here and there over a few days.

Still pulling p0505 code with NO illuminated engine light. Car is running fine.

Anyone know why this code isnt causing my light to come on?

Does anyone thing my idle relearn procedure didnt take and needs to be programmed via dealer?

Really kind of lost here.

[yngw13]

Im in the same boat...
Hitachi IACV but getting P0505...

Runs great....

What a head scratcher...

[TheReplay]

Well i brought my car to the dealer, he did the idle air relearn via his consult 2(?) Tool.

I let him know my scanner reads codes but no light. He informed me that the vehicle is not "showing" and i just need to complete a drive cycle to clear whatever is there right now.

Will report back after 100 miles or so..

YNGW13 you are pulling code p0505 after replacing IAC valve.. did you also need to repair the ECM? Do you have an illuminated engine in conjuction with the code?

On a side note.. even though my car is old and not in great shape, the infiniti dealers always seem to treat me well and with respect.. cant say as much for nissan dealers ive dealt with. Makes me glad to have went the infiniti route over the nissan.

[yngw13]

Hi Replay,

The truck still runs and idles great as it should...waiting for the worst to happen with the light on
Emission will be around Sept hopefully I can change out the Hitachi with a legit OEM...I dunno why the ECM would blow with the "new" part...Im guessing the voltage is not passing for the ECM to clear the code ---stumped

[sroberts]

yngw13, I'm pretty sure "legit OEM" is now Hitachi, but perhaps you can find some old stock.

The ECM can obviously blow with a new part if the part becomes defective. Within a year of replacing my IACV/ECM my pathfinder developed idle problems and registered a P0505, and I found the resistance values of the IACV solenoid to out of (lower than) spec described in the EC manual. I believe the lower the resistance of the IACV, the higher the chance of damaging the ECM. Replacing the IACV again corrected the problem.

[yngw13]

yngw13, I'm pretty sure "legit OEM" is now Hitachi, but perhaps you can find some old stock.

The ECM can obviously blow with a new part if the part becomes defective. Within a year of replacing my IACV/ECM my pathfinder developed idle problems and registered a P0505, and I found the resistance values of the IACV solenoid to out of (lower than) spec described in the EC manual. I believe the lower the resistance of the IACV, the higher the chance of damaging the ECM. Replacing the IACV again corrected the problem.

Thanks for sharing...emissions is due around September so I might have to figure out why Im getting P0505 codes despite the new part (Hitachi ABV0043) my next solution would be to purchase direct from Dealer.

[sroberts]

If you can spare having your truck out of commission for a couple of days, you may want to examine the part from the dealer before handing over the $300 or so, and if it is the Hitachi, order it online. In this thread topic607957.html I compared my recent "OEM" purchase to the Hitachi IACV that failed. The more expensive "Hitachi OEM" part (top) is exactly the same:

[yngw13]

Hi SROBERTS

Can you detail me as to where to get the OEM?(your source) I have the Hitachi as you pictured (with the sticker like mine). I was hoping not to get @dealer $price.

Thanks bud!

ALSO----

are the procedures as to IACV replacement? - Am I required to disconnect battery and redo a relearn after install?

[Buzzman]

I had the battery disconnected when I swapped mine out, but that was more to do with the ECM also being out.
Still, I would disconnect the battery, just to be safe.
You will more than likely have to do the re-learn again too. The new IACV will not know where it's "home" position is.
Your idle will probably be too high when you fire it up.

[TheReplay]

So heres my update to the original problem...

Picked up my car from the dealer... p0505 code was gone, but not sure if it cleared itself or if they cleared it with an idle relearn (which they confirmed they did).

P1448 and P0455 were on, but again no illumination of engine light.

Dealer told me to drive it and see if it completes the emissions cycle.

They did the recall on my rusted wheel/strut housing (last time they put the spray, this time they put the bracket). They didnt charge me for the idle relearn, or diagnosis, which i thought was really great of them.

Drove it all weekend, hoping the code would clear, but unfortunately at around the 90 mile mark the engine light came on and the codes read double (4 codes, duplicate p1448 p0455)

I checked/tested the evap canister vent control valve @ the rear bumper, and when i found it to be working i also checked/tested the purge/volume valve on top of the manifold and the pressure valve back where the canister is. I blew out the lines (they were clean) and just said screw it and ordered a new vent control valve. I also picked up a new gas cap @ the parts store. I did NOT replace the gas cap yet as i wanted to isolate this.

I replaced the vent control valve and drove it all day yesterday, (p1448 and p0455 did not return) now i was getting a code for p1441 (small leak), also no engine light on.

Installed new gas cap, reset the codes and drove on...

happy to say that now I am getting a green/pass light for emissions... its been a long while since ive seen that on my vehicle.

[yngw13]

So asides from the recall...

All they did was an idle relearn via OBD tool?
No parts replaced?

I will have go to a dealer nearby and have them do a OBD tool relearn.
This gives me hope...not suffering from bad idle...just need peace of mind

[TheReplay]

No parts replaced.. just did an idle relearn.. as i said im not sure if the code cleared itself or if they cleared it, or if it cleared with the relearn..

[yngw13]

I might just go to a dealer also to get that done...or was thinking of just having it driven for awhile so that it just might clear the code and since it has been idling fine anyways . Initially I was thinking of getting another IACV but then it would be too wasteful.

thanks

[yngw13]

so after 3 IACV replacements and still P0505 i returned the ECM to Circuit Board Mechanics for warranty repair. Needless to say they found "strange things" happening to my ECM and fixed it. I installed it then no more P0505. Kudos to Circuit Board Mechanics even though I had to return it I felt the warranty for a year covers any mishaps. BUT I encountered P0158/P0138 code...but then it was because I havent changed oil in a span of a year and a half as I dont put much miles. Reset again and the codes after 200 miles never came back. Got an emissions inspection and required me to have the leaky exhaust system fixed. I had to go back twice and what a PIA. Finally the truck is again emission passed and dont have to worry about it for now. Maybe next will have to install new upper trailing arms and polyurethane bushing for the lowers.

[04pathse]

it was because I havent changed oil in a span of a year and a half as I dont put much miles.

Probably shouldn't go quite that long, some people say maximum 1 year if you must, but best to change every 6 months no matter what miles are driven.