2012 QX56 - P062B code - Sputtering and loss of power

[primov8]

Ever since I cleaned out the valves, I've meticulously used CRC GDI cleaner right before every oil change interval (4K miles). The one thing I do differently is not spraying directly into the throttle body for the majority of the cleaning process. The top of the intake manifold has a vacuum port on both sides of the manifold. Those hoses are connected to the PCV valves and help contribute to the carbon buildup in these GDI motors. After spraying the throttle body for about minute to start off the process, I then disconnect a PCV hose and spend a good 1-2 mins spraying into the manifold; then switch over to the other side. I keep doing this until the can is done.

 

[Timanton]

I had this problem for months. it drove me crazy. I bought i a new ECM and that was not it. i dont recommend buying one. The little i could find online said it might be the wiring harness but i tested the resistance to each coil and everything was fine. so the next step was to take the intake manifold off and check the injectors. i was just guessing at this point. so i get the intake off and start to pull the injectors out when i notice the valves were absolutely full of carbon buildup. im talking like a quarter-inch thick. it (pic in link below) took me hours to clean but i got it done and i also changed the spark plugs and the code went away. this is something i spent months and a thousand dollars on and it ended up being something simple. i would absolutely check the valves first and spark plugs. i don't know if you have a scanner where you can test each cylinder but 7 and 4 were not working for me, it was the spark plugs. Photos-001

@Mhead55 - My 2010 QX56 was doing the same thing… throwing codes about communication from the ECM and TCM. Going into limp mode, etc. This post was a lifesaver! I followed what you suggested… I removed the intake manifold and cleaned it completely. I also cleaned some of the carbon from the cylinders carefully and replaced the gaskets. While it was off, I replaced the starter (since it is under the intake manifold). I also replaced the spark plugs. I was considering replacing the ECM and wiring harness but figured I would try this first. So glad I did. It has been a couple weeks and all is running great. No codes and really no issues at all. So glad I found this post. Looks like it saved me thousands.

 

[clpearson79]

Hey all, I am so glad I found this forum! I was having a similar issue (P062B, P0172, loss of power and running rough) and of course I was told to replace the ECM. My husband sent it off for repair instead, and of course that made no difference. I found this forum and insisted we open up the engine and take a look at the valves. They were really bad. Took me 8 hours to get them cleaned out, but finally got them clean. Also changed the spark plugs and the starter while we were in there.

Now, she idles fine once she is started and runs ok (still seems to be in limp mode but not running rough), but she’s having trouble getting started. The starter turns fine but when she starts she is idling low (almost like she’s going to stall), then the engine surges, throws a P062B code before going back to a perfect idle. Any ideas? I plan to drive her around for a bit in case I just didn’t run her long enough to let the carbon clear. Thanks!

 

[Abdul88]

Hey all, I am so glad I found this forum! I was having a similar issue (P062B, P0172, loss of power and running rough) and of course I was told to replace the ECM. My husband sent it off for repair instead, and of course that made no difference. I found this forum and insisted we open up the engine and take a look at the valves. They were really bad. Took me 8 hours to get them cleaned out, but finally got them clean. Also changed the spark plugs and the starter while we were in there.

Now, she idles fine once she is started and runs ok (still seems to be in limp mode but not running rough), but she’s having trouble getting started. The starter turns fine but when she starts she is idling low (almost like she’s going to stall), then the engine surges, throws a P062B code before going back to a perfect idle. Any ideas? I plan to drive her around for a bit in case I just didn’t run her long enough to let the carbon clear. Thanks!

I have the solution you can contact me

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[primov8]

^^^^ More like trying to sell BS. If this guy really has a so-called "solution" why not post it on the forum and help those trying to fix their trucks.

Carbon buildup is notorious on GDI motors and unfortunately, Nissan hasn't adapted by integrating port injection with direct injection.

@clpearson79, great job on cleaning those valves up. If you're still having idle issues, you're going to need to do a couple reset/relearn procedures. A full range scan tool will do all the necessary relearn procedures with just a couple prompts but if not available, follow these steps:

https://uprev.com/documentation/Resets-for-Nissan-Infiniti-Functions.pdf

 

[clpearson79]

^^^^ More like trying to sell BS. If this guy really has a so-called "solution" why not post it on the forum and help those trying to fix their trucks.

Carbon buildup is notorious on GDI motors and unfortunately, Nissan hasn't adapted by integrating port injection with direct injection.

@clpearson79, great job on cleaning those valves up. If you're still having idle issues, you're going to need to do a couple reset/relearn procedures. A full range scan tool will do all the necessary relearn procedures with just a couple prompts but if not available, follow these steps:

https://uprev.com/documentation/Resets-for-Nissan-Infiniti-Functions.pdf

Thanks, I thought it might be something like that. She runs better than ever, if I can just get her to start without sputtering I think we’ll be GTG.

 

[primov8]

Thanks, I thought it might be something like that. She runs better than ever, if I can just get her to start without sputtering I think we’ll be GTG.

I also recommend using CRC GDI intake valve cleaner as part of the routine maintenance. I like to change the oil every 4K miles and right before doing so, I always treat the engine with this cleaner.

 

[drewdogg808]

Does anyone have a DIY for cleaning the valves? My 2011 is at the dealer now and I was also quoted $8100 to replace the f-harness, ecm, relays. I've had more issues with this car than the other 3-4 vehicles I've had in the past 15-20 years. Should have traded it in years ago.

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[gmarch7]

Does anyone have a DIY for cleaning the valves? My 2011 is at the dealer now and I was also quoted $8100 to replace the f-harness, ecm, relays. I've had more issues with this car than the other 3-4 vehicles I've had in the past 15-20 years. Should have traded it in years ago.

Click the link in comment #43 in this post

 

[clpearson79]

Well, I’m still having the same starting issue. Still throwing the P062B along with the occasional fuel too rich code. Sometimes she stalls out, sometimes she starts right up. Happy for any other suggestions.
So far, we have:
Had the injectors tested/professionally cleaned & gaskets replaced.
Cleaned the fuel rail.
Cleaned the valves by hand, twice.
Cleaned the mass airflow sensor.
Had the ECU serviced/tested, twice.
Performed the resetting procedure suggested above.

Thanks for any help!

 

[primov8]

Well, I’m still having the same starting issue. Still throwing the P062B along with the occasional fuel too rich code. Sometimes she stalls out, sometimes she starts right up. Happy for any other suggestions.
So far, we have:
Had the injectors tested/professionally cleaned & gaskets replaced.
Cleaned the fuel rail.
Cleaned the valves by hand, twice.
Cleaned the mass airflow sensor.
Had the ECU serviced/tested, twice.
Performed the resetting procedure suggested above.

Thanks for any help!

Any chance you have access to or know a reputable shop with a full range scan tool that can read live data? One thing to check out would be the data from the "FUEL PRES SEN V" which is the high pressure fuel pump. You can't check actual fuel pressure on these pumps so it's diagnosed by the range of mV it puts out. At idle, it should be between 820 - 1.220 mV; a quick rev from idle to 4000 rpms should yield between 820 - 3.060 mV.

 

[Jmac]

We recently just purchased a 2012 QX56 with 100k on it. 4 weeks after purchase the vehicle threw a P062B code. The engine started sputtering and loss of power going uphill. This does not happen constantly, it comes and goes. Took it to dealership and they tell us that 2 wire harnesses for ECM & 1 relay need replacing. Grand total of $9000.00 to replace them. Has anyone experienced this issue before? I find it difficult to believe that 2 wire harnesses cost 9k to replace.

Yes this sounds like my exact nightmare I'm going through. Can you tell me your outcome?

Yes this sounds like my exact nightmare I'm going through. Can you tell me your outcome?

Has anyone discovered the real fix for this P062B code? Does the 9,000.00 repair of exam, relay, and harness truly solve this issue?

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[Nickdadon561]

So just a update, I finally gave up and took my QX56 to a dealer a couple weeks back. The first time I took it in they told me it was a bad ECM and replaced it. After they told me it was good to pick up and $2000 later, I made it about 10 miles and the code came back along with loss of power and sputtering. So I took it back again and they said it was a bad injection relay causing the ECM to burn up, so yet another ECM and if your counting thats now 4 ECM's, 2 wiring harnesses, 3 relays and alot of dough and head ache! Well now I go and pick car up a second time after being reassured the problem had been fixed...and what ya know by the time I got home P062B is back...AAHHHHGGGGGG!!! What the hell!
If between two separate dealerships and now what seams to be endless time and money, this Nissan/Infinity turd is still not repairable, why not stand by your product and admit you created a problem child and RECALL this piece of shit!!! Japan should stick to robots, sushi, and swords because they cant make a decent car! I have lost my patience!!! Maybe we need to get the guy who actually engineered this thing to come take a look, because every one else is just guessing at this point. If your having these problems, you may have just purchased a parts car...good luck your going to need it. Im going back to chevy at least when they break you can fix them.

 

[G-404100]

I have the these same problems! Should I just sell it in parts? lol

 

[marctronixx]

thats entirely up to you. if you dont think the car is worth it, sell it.

 

[clpearson79]

I have the these same problems! Should I just sell it in parts? lol

I posted above, and I am STILL having issues with mine. I’ve taken it to several mechanics and replaced a ridiculous number of parts…and the same issue still exists but now I have some new problems along with it. None of the mechanics have been able to figure out the issue. The most recent said his next step would be to test the wiring harness pin by pin.

Thankfully, in my case the Infiniti isn’t my daily driver so I’m in no rush to fix it, but it’s been having issues for over a year now which is utterly ridiculous.

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[marctronixx]

electrical gremlins are difficult to find for any car. its lengthy and time consuming, so they bill accordingly. perhaps at some point it becomes a burden and you need to move on with life...

 

[G-977835]

Hi having the same issues with a Y62 has anyone found the real issue and fixed??

 

[BernardWilliamso]

We recently just purchased a 2012 QX56 with 100k on it. 4 weeks after purchase the vehicle threw a P062B code. The engine started sputtering and loss of power going uphill. This does not happen constantly, it comes and goes. Took it to dealership and they tell us that 2 wire harnesses for ECM & 1 relay need replacing. Grand total of $9000.00 to replace them. Has anyone experienced this issue before? I find it difficult to believe that 2 wire harnesses cost 9k to replace.

I doubt that's it at this point, unless it's somehow freaking out the computer (that's tech talk). I've had batteries going bad that made a watch run faster instead of slowing/stopping.

 

[Guss]

So just a update. As of all last week my QX56 has been running great....until about a hour ago! I thought for sure I had maybe corrected the problem by replacing relays, new battery and cleaning up all electrical connections, but I guess I was just just being optimistic. I had a scanner hooked to it all last week just waiting for it to act up, so that maybe I catch a irregularity in the live graph. Unfortunately I removed scanner to soon and missed that critical moment of failure. Now im back to no power, sputtering and very high revs before shifting. I did notice this time when it started acting up, I was sitting in drive through holding the brake and at the exact time it started sputtering the vehicle lunged forward as if I let off the brake, that could have been a oh shit moment had there been a car in front of me. I believe Nissan / Infiniti needs to recall this vehicle, its un safe and very unpredictable! By far the most troublesome vehicle I have ever owned, and im not eager about sinking $5000+ into a vehicle thats only bringing $12,000 - $14000 and only hope it fixes it in the long run. I believe it would become a new fish habitat in the lake behind my house before going down that rabbit hole.
I am going to re install scanner and see what I can see now that its schizophrenia personality has showed up again . Most likely the ECU will be coming out this week and be sent off for repair and re-flash and hope for the best. I will keep this thread up dated if I find anything out of the norm or have any luck.

Hey brother I'm experiencing the same thing on my wife's 2012 QX56. I've been meeting a lot of scammers online about ecm repairs. Can you please tell me who you used to send your ECM off to repair or reflash. Thank you.