2001 Infiniti QX4 IACV and ECM question

[apvm]

Hi, I have the QX4 IACV and ECM problem and my local shop is going to charge $1000 to fix. I have the QX4 towed back home. Planning to buy HITACHI ABV0043 to just replace the black sensor since replacing the valve body would be too much for my skill. I can see where the ECM is located but have no idea how to get it out.

My question is :

Will just replacing the IACV sensor do? and how to take the ECM out? Please kindly help as I could not find any instructions on how to take it out. Main is what to do after disconnecting the connector to the ECM. TIA

By the way, planning to use this service to fix the ECM since I am from Canada. http://www.ebay.ca/itm/230744291843?_tr ... EBIDX%3AIT

[apvm]

I disconnected the battery and waited 5 minutes. Disconnected the connector to the ECU/ECM. what is my next step? Please.

[Buzzman]

OK, so I went through this two years ago on my 2002 Pathfinder. I'm also in Canada.
At the time that it happened, I was getting ready to travel to Florida for two months (winter), so I took my ECM with me to the states, and sent it to be repaired down there.
I also bought my IACV down there, which was cheaper than back home. All this to say that I'm not familiar with the company that you plan to use.
I paid $250 for the ECM repair. It was probably too much compared to your ebay folks, but I was confident in the Company I was dealing with.
As for getting the ECM out, it's a bit of a pain.
There's a bracket that holds it in place, and you'll need a 10mm socket to undo the bolts/nuts.
You'll also probably have to cut a few ty-raps on the wiring harnesses that are crammed in and around there in order to wiggle it out.

Now, as for your question regarding just replacing the IACV, that depends on whether you know for sure if the ECM is fried.
Question is, was/is the truck still idling, or is it dying?
FYI, replacing just the IACV will not hurt it. Even if the ECM is damaged, it will not kill your new IACV.
If you replace it, and the truck then runs (probably with a fast idle), then you may have dodged a bullet, and you will only have to do a relearn.
If the problem is the same with a new IACV, then your ECM needs to be repaired.

The $1,000 quote from your shop is robbery.

[apvm]

I know the ECM is fried for sure, I can smell it. Right now it won't start and the code is P0505. Do I need to remove anything else to get to the bolt/nuts? Thanks again for your help. I know the shop is expensive, he quoted $495 plus tax for the IACV while rockauto has a Hitachi one for $90 plus shipping and taxes.

[Buzzman]

That shop quote for the IACV is not that far off if you were to compare the parts price from the dealership.
Nissan price was over $300 when I shopped around two years ago. I'm guessing the shop is building in a little profit on the part.

I was able to get at the ECM by just removing the lower panel under the steering wheel.
Like I said,I found that the other wiring harnesses that are under there were in the way more than anything else. It's awkward.
When I re-installed it, I didn't bother with the bracket. Good luck.

[apvm]

Thank you so much for the help. One last question, did you just replace the black round sensor or the whole thing including the valve body?

[Buzzman]

Thank you so much for the help. One last question, did you just replace the black round sensor or the whole thing including the valve body?

I ordered the part from a Nissan dealer while in Florida.
I was originally going to just order the black valve, but then the valve and body assembly was only like 20 bucks more, so I bought the assembly.
I'm actually glad I did. The old valve body was corroded pretty badly, and it turns out it was leaking coolant there. It also came with the necessary gasket, which was toast on my old one.
It also gave me a chance to clean up the throttle body. It was pretty dirty.
Here's a few pics:

[Buzzman]

One last thing. I may have led you astray on the bracket thing for the ECM.
I was rethinking what I did, and I'm thinking now that you have to use the bracket.
I remember for sure though not putting back all the screws and nuts. Half of them are redundant. As long as it's secure, you'll be good to go.

[apvm]

Thank you again for your help. I think I'll leave the valve body alone since it looks like it will be out of my skill level. Don't want to touch that part unless I have to. By the way, about the lower panel, I can only find one screw that is located on the right but according to a diagram there is suppose to be another screw on the left under the coin tray but I can't find it. Thanks.

[Buzzman]

Been a couple of years since I took that panel off, and right now it's -20C and dark, so I'll have to wait until tomorrow to have a look. Sorry.

[apvm]

No problem. I am waiting for Tuesday since the weatherman said it will be 4 degree before I'll start work. Southwest Ontario here.

[Buzzman]

Southwest Ontario here.

I'm in Ottawa. Freekin' cold weekend. Supposed to get "warmer" this week. Fingers crossed.
I hate winter. We had planned to go to Florida again this year, but had to cancel. (Have some corrective surgery coming up at the end of the month).Sucks.

[apvm]

Took the ecu out. Easier than I thought after the lower panel is removed. Thanks for all the tips.

[Buzzman]

Hey, that's great. It looks like it's just you and me chatting here, but I'd like to know how it all ends up. Keep posting. Cheers. Go Sens.

[apvm]

Sent it to Module Repair Pro Inc in California for repair, turn around time should be at least 2-3 weeks. Meanwhile ordered the Hitachi IACV from Rockauto. This is my plan:

1) Once IACV arrived will just clean throttle body with cleaner and replace the black sensor only. I may not be skill enough to replace the valve body and I don't have the power tools to remove the screws like what you did.
2) Wait for ECU and reconnect and hope it will start.

By the way, did you change the Throttle position sensor as well?

Thanks.

[Buzzman]

You should be OK. No need to pull the throttle body if you don't have any other problems.
I pulled mine off because I had a very tiny coolant leak at the IACV body.
I did not replace the TPS sensor. No need to do that.
The truck should start no problem once everything is hooked up. Hopefully you are doing all this with the battery disconnected.
The only other thing you will have to do is an idle relearn.
After I put mine back together, it idled at just over 1000 RPM's. The idle was rock steady though, so I knew everything was OK.
I tried the relearn procedure outlined in the FSM, and on this site, but never got it right.
I took it to my techy at the dealership (also a personal friend), and he did the relearn in about 5 minutes with his scan tool, at no charge.
The engine has been running perfectly ever since.
I can't comment on the turnaround time.
I took my ECM with me when I went south for two months in the winter, and sent it out for repair while I was down there.
I brought it back with me and put the stuff back together when I got home. The only problem I had when I got back was a dead battery.
Good luck.

[apvm]

Oh no...I did not disconnect the battery when I took the ECU out, hope it will not cause any problem...

Well, it will take about 1 week to get there and 1 week back, in any case they should know if I have fried the ecu by not disconnect the battery while removing it.

[Buzzman]

Hopefully they'll fix everything that is wrong with the ECM.
If you haven't disconnected the battery, I'd do it now.
Be absolutely sure you leave the battery disconnected when reassembling everything.
Do not connect it back up until everything is plugged in and double checked. Good luck.

[apvm]

Will do. ECU repaired and is now on its way back, following is what Module Repair Pro Inc commented:

"Your ECU had a burned chip controller that works with the Idle Control Valve. Typical picture. Chip replaced, circuit board repaired. Passed bench test for IAC valve performance.
Your no-start condition is outside of the ECU itself, check ECU fuse, wiring harness, etc."

Now my IACV shipment is at Buffalo but Rockauto uses Landmark as shipping agent, it may stay there for a while.

[apvm]

IAC arrived, will change that on Sunday. ECU should arrive early next week. Hopefully, the QX4 will start.

[Buzzman]

Keep us posted. Good luck.

[apvm]

Put everything back togather except I dropped the screw on the left to tighten the lower panel into a black hole below which is now no where to be found, no big deal. Now another problem, after about 26 days sitting in the cold, the battery is dead and I don't know if the fix works or not until I try to jump start it tomorrow. Too late now and very tired.

[apvm]

It won't start and security light stays on after cranking, it that normal? TIA

[apvm]

Checked with OBDII tool, it won't see the ecu, interface bus ok but can not connect to ecu according to the program. I have also checked both fuse, they are ok.

[yngw13]

maybe double check that your ECM is firmly connected to the plug/pins. sorry that this didnt take on the first go...
I had my own problems...I had to return the ECM because the CEL light wont go away...2nd take good to go...now I just get O2 sensor codes ...

[sroberts]

May be a long shot but consider double checking the ECC2 fuse or swap it with a known working one. I had the same issue where my car would not start after replacing the ECM. I'd checked the fuse with a continuity tester and got a beep but it turned out the fuse was borderline and apparently was not completing the circuit when plugged in.

[apvm]

Ended up may have to tow it to the garage. This guy during Christmas when I had the ecu and IVAC problem did a quick fix by adding a relay to the fuse/relay box under the hood on the passenger side. It started and I could drove it home, although with over 1000rpm when idle but the next morning it won't start again. I knew I was scammed $400 (stupid me) fast forward, I had the IVAC and ecu fixed but if I remove the relay, it won't start and I notice I could not connect to the ecu via obdII (no power/no vehicle) I suspect power was cut if I remove this relay. If it was plugged, I could start and connect to ecu via obdII.

The relay is a 12V 20A/30A with a number AR. 502, 4 wires two connected to ground and two to the relay box. I took the relay out and reconnected the two wires (color to color) but the car won't start and no power to the ECU, if I reconnect the relay, it start again.

I suspect he has disconnected more wires in the relay box but this is out of my skill level. I am not going to fix it myself but would like someone with knowledge to electrical system tell me what did he done to my QX4? TIA

By the way, the guy who did this is not answering my phone and texted me that he is out of town, he was stalling me since last week when I asked him to remove the relay and put the car back to original state.

[apvm]

For those who only replaced the black motor of the IACV without the body needs to aware that the failure of that black sensor/motor is mainly due to coolant leak, if you don't replace the body, the black thing will fail within a year or two and the same problem will repeat itself again.

Also confirmed by an experienced Nissan mechanic that the Hitachi part is the same as the Nissan part, Hitachi is the OE manufacturer.

The proper way to have this fixed is like what Buzzman did, replace the whole unit to avoid future problems.

[04pathse]

Sounds like the IACV is shorting because of the coolant contacting the electrical bits in the IACV so I guess that is because of the IACV rubber gasket failing after about 10 years or so, that means that you should replace the gasket to prevent the leakage before the gasket fails, right?


https://www.vividracing.com/catalog/-p- ... wAodAJ8AIw

[apvm]

Most likely.