2001 Nissan Pathfinder 4x4 ECM - P0505 code

[BTroop]

Hi everyone. Thanks in advance for your assistance. A few weeks ago, my 2000 Pathfinder 4x4 crapped out for no reason on the highway. No engine or service lights were on. It was running great prior to that. I had to have it towed and the mechanic said he thought it was the fuel pump and suggested that be replaced. We did that and he then called to say the car was still not idling properly and that it probably was the IACV and possibly the ECM. After further discussion, we agreed to have him replace he IACV. After this was replaced, he called to say that the car runs, but still has a low idle and stalls out. He definitely now states he believes it is the ECM and that the P0505 code is pulling. Still no engine lights/service lights on. I questioned him about getting an ECM online or from a junkyard and he was definitely not for that at all, even going with the IACV from ebay, etc. he was against it. Just for the IACV, he said the part cost $400. I found your forum and see that a lot you folks have sent out the ECM to the suggested companies to have it repaired. I am thinking about doing this, however, I am afraid that I will have to reprogram the keys and the computer (ECM) after it is taken out and re-installed. I don't have the equipment obviously to do so. I am already into this about $1,100 and have a car that is not reliable and stalls out. No one would want to buy this problem! The Pathy is in great shape and only has 144K on it. I just am not sure I want to put anymore into it. I am so far into this and maybe I should just part it out or donate it. Any suggestions? Thank you all so much.

[macgiver]

mac, I've seen people on youtube replace the single "driver" transistor inside the ECM , on ckt board which looked like an easy solder job. Yeah it seems a common problem and surprising Nissan's engineering couldn't have made either IACV not prone to "Dead-short" OR design the transistor driver ckt. more "bullet-proof" (easier one) . And I would think (having electronics exp.) that SOME out there would have , if repaired , or as preventive meas. to introduce - in series - a small , fast-blow micro fuse , best installed out at the leg of the IACV which "shorts" -overcurrent ! Values like 25,50,75,100ma & higher available I believe. You might try to contact a you-tuber who's shown to do this ? I didn't notice the notion of adding the "protective micro-fuse" though , and it's ma value would have to be commensurate with being well below the replacement x-sistor's ma rating of the "Collector". Added or better "heat-sinking" of the x-sistor always helps , especially in a high temp environment!

[04pathse]

You can get an Hitachi IACV (which is the same as the OEM) for around $100, there are a few aftermarket IACV's out there for less but I would definitely go with the Hitachi IACV.

https://www.amazon.com/Hitachi-ABV0043- ... B00CMWGIMI

I have seen several places on Ebay that can do the ECM repair for as low as $75 (depending on the ebay seller)

https://www.ebay.com/sch/i.html?_from=R ... r&_sacat=0

You do not have to have the keys reprogrammed, you only will have to have to do the idle relearn and maybe a few other relearn procedures but you definitely don't need the keys reprogrammed.

There are several threads on here on the issue and the repair, you can do a SEARCH for the threads.

[jarretw]

I wanted to share some knowledge. I went through this issue where my IACV failed and caused my ECM chip to fail as well.

Car ran poorly then eventually died. Gave all of the codes to signal failed IACV and ECM.

Rather than spend the 1K to get the new ECM at Nissan or even the $250 USD if you sent it away at one of sites who repairs them when you send them away, I went even cheaper.

I replaced the IACV myself and got parts from rockauto.com

I removed the ECM https://www.youtube.com/watch?v=YnnLuXIJu-g

After that I looked online to find a way to repair the ECM the cheapest possible. If found a video of a gentleman replacing the chip that fails inside of the ECM when the IACV fails. https://www.youtube.com/watch?v=dMqLEjbK4FY

He tells you to buy the chip from amazon (ships the quickest of what I found) $10 for the chip, $30 to get it shipped to me to Canada in less that 2 weeks. The chip is an STA509A. This is the one I got in Canada from amazon.ca https://www.amazon.ca/Lysee-STA509A-STA ... -1-catcorr

I took my ECM with the burnt out chip, as is the same in the video above, and my new chip to an electronics store guy in town, he removed the old chip, replaced it with the new one and soldered it in for me for $60 bucks.

Put the repaired ECM back in the car and it runs as good as it ever has.

Repair at Nissan:
IACV $250 + shop time
ECU $1000 + shop time

Repair at home:
IACV $150
ECU $100