2012 QX56 - P062B code - Sputtering and loss of power

Franklypissed

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So your qx56 was sputtering and losing power due to low voltage? I think our daytime running lights are always on when we drive but I will double check that. Did you mean day time running lights or regular night time head lights?

Thank you for your input. I have had little luck trying to fins anyone that has had my same problem.

Replaced the ECM & EGI Wiring Harness. $3500.00 and the problem has not returned. Also had the catalytic converter location modified. We cleaned out the insides of the original cat and welded in a new cat down the exhaust a little bit so that in the future we would not have to replace the entire exhaust manifold because of cat issues. Relocated both sensors as well.


What are the specs for moving the catalytics down?
 

cecil B

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I have a 2012 Infiniti QX 56. I am having the same issues as so many people have posted in this forum. My issues are very sporadic. They include miss fires, power loss and so forth. The conditions are not isolated to the engine, they also affect the way the vehicle shifts and the ability to get out of park sometimes. The vehicle can go from running great one day to not being able to pull itself up a hill the next. You can definitely notice a shift in the power curve when it starts acting up. When its bad, I usually have to manually shift it and keep the RPMs above 4,000 just to get over a hill. To me when it starts acting up it sounds and feels like the valve timing is way off and I can actually hear that hollow sound through the intake on acceleration.

The codes it is throwing are the infamous P062B internal control module, P0130 oxygen sensor, and P0300 miss fires. The wiring harness, timing chains, relay, and O2 sensors were replaced before the warranty ran out, before I purchased the vehicle.
I personally have replaced the battery and all relays. I have also went through every harness connection and cleaned every ground down to bare metal. My problem goes away for a short time then re appears, almost like a cycle.
I have read through all the forums and from what I am seeing is that nothing ever works or there is no follow up. I am reluctant on taking it to a dealership only to end up with a shotgun repair. I am very mechanical and work on large equipment for a living and believe I can fix the issue myself.
I am just having trouble tracking this issue down as I am confident it is electrical due to the sporadic nature and that it seems to affect both engine and transmission.
I have read in on multiple forums people have had the same issue and taken it to the dealership only to spend $5000+ on every thing from new cats, O2 sensors, MAP sensors, timing chains, wiring harness, ECM, etc and never fix the issue.
So I guess my question here is, the timing chain, battery, wiring harness, relays have already been replaced do I move on to ECM? I dont have a lot of money and am struggling here, has any one had any long term luck with a particular fix for this issue? Any help here would be greatly appreciated. Thanks.

I had replaced my ecm and engine wire harness and after 5 months it happens again
What did work , if anything?

I had the same issue it came back again
Did anything ever work?
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marctronixx

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ive had a 2012 rully loaded with no issues, so the car is a solid performer. sorry to hear of your troubles.

since you have done all that you said you did, the ECM and BCM are next in line. even those parts you replaced , one of them could be faulty, so dont think just because you replaced them that they are good.

could be O2 sensor related, CAT related.

at the end of the day infiniti will charge you what 90 bucks to do a diagnose? i think it may be worth it to have them use their CONSULT tool and such to try and track down some other issues. since you are good at repairing yourself, you can then take their advice and look at those areas.

since its the internet, none of us know your car's history, only you do, nor can we look at the car, so we are at the mercy of what you tell us. speculation abounds , and at some point the you will get many ideas from random people, which can confuse things. taking it to a dealer and having them do some legwork for you may be worth the investment.
 

primov8

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@ cecil B. My QX80 hasn't encountered the issues I've read here related to the P062B DTC. Like you, I feel its electrical related and as crazy as it sounds, the ECM controlled alternator could be part of this problem.
The battery current sensor attaches to the negative battery. With the harness unplugged and ignition ON, signal wire for the ECM controlled wire reads out at approx 2.5V. You can either de-pin or cut the wire; I cut the wire and spliced on bullet connectors so when I would bring the truck in for annual emmissions (NYC), I would connect it back on so it wouldn't trigger a DTC for the battery current sensor.
Why do this? The alternator now works as a traditional charging alternator. My Northstar battery is always a constant 14V+, even with the A/C running. Even at rest, the lowest I've seen the battery voltage was around 12.9V. We all know a weak or failing battery can throw in a mix of electrical issues so this DIY wouldn't hurt ruling out the ECM controlled alternator being a possible cause of this issue.
 

cecil B

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@ cecil B. My QX80 hasn't encountered the issues I've read here related to the P062B DTC. Like you, I feel its electrical related and as crazy as it sounds, the ECM controlled alternator could be part of this problem.
The battery current sensor attaches to the negative battery. With the harness unplugged and ignition ON, signal wire for the ECM controlled wire reads out at approx 2.5V. You can either de-pin or cut the wire; I cut the wire and spliced on bullet connectors so when I would bring the truck in for annual emmissions (NYC), I would connect it back on so it wouldn't trigger a DTC for the battery current sensor.
Why do this? The alternator now works as a traditional charging alternator. My Northstar battery is always a constant 14V+, even with the A/C running. Even at rest, the lowest I've seen the battery voltage was around 12.9V. We all know a weak or failing battery can throw in a mix of electrical issues so this DIY wouldn't hurt ruling out the ECM controlled alternator being a possible cause of this issue.

Thanks for the suggestion. I will check this out for sure before moving on.
 

Garage1881

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WE just purchased a 2011 QX56 and it is doing the same thing. I'm going to get the codes pulled in the morning. Hopefully its not this, but I'm afraid it is.
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cecil B

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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.
 
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Garage1881

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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.

Any updates on this?
 

cecil B

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So I have no real update as of yet. I have been driving a second vehicle and just had to take a break from the QX56. After collecting data for a while now under various driving conditions and eliminating possible bad sensors vs bad ECU readings with analog test equipment, I am almost certain its the ECU. After talking to a Infiniti dealer, I found this vehicle has actually had the ECU and harness replaced twice before not just once as I thought.
So now im more incline to discover why the ECU is failing in the first place before spending more money on a new or rebuilt one. Oddly enough I took her for a spin today and from the start it was a little touch and go but then she pulled her typical personality flip and ran like a champ.
Even if Infiniti dont have the answers....I will find them!
 
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dougracezs

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So I have no real update as of yet. I have been driving a second vehicle and just had to take a break from the QX56. After collecting data for a while now under various driving conditions and eliminating possible bad sensors vs bad ECU readings with analog test equipment, I am almost certain its the ECU. After talking to a Infiniti dealer, I found this vehicle has actually had the ECU and harness replaced twice before not just once as I thought.
So now im more incline to discover why the ECU is failing in the first place before spending more money on a new or rebuilt one. Oddly enough I took her for a spin today and from the start it was a little touch and go but then she pulled her typical personality flip and ran like a champ.
Even if Infiniti dont have the answers....I will find them!

check intake runners and valves. they get clogged with carbon build up due to the direct injection. pm me if you have any questions
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Aljgomez

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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 have the same issue I thought my transmission was slipping as I was noticing it having a hard time climbing the overpass and when I got home I shut the car off to see if my transmission fluid was low.. found out that one cannot simply check the transmission fluid level in these vehicles or the 2011-up models.. I go to turn the suv on and that’s when I noticed the engine running rough misfiring unable to go past 3000 rpm. I scan the obd2 and get the P062b and here I am trying to get a hint of what to look for 1st. Hate to take it to the dealer to get bad news.
 

cecil B

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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.
 

mmwhite8075

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Hi, having this same issue. I am also showing codes P0172, P0175, P0133 in addition to P062B. Going to start with the basics; battery looking for cut wires in the harness and then go on from there. Thanks for all the info you guys have provided.
 

M I Z

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Hello There!,
2012 QX56, 65K miles. Vehicle is in Canada but originally purchased in the US.

Exactly the same issue with mine since 1 week ago.
Sputtering engine, transmission shifting wrong, P062B, P0172 and P0175 showed up. Car starts normal then it starts acting up but when turned off and on again sometimes it "clears" itself until it happens again maybe the same day or the day after. Noticed it doesn't happen when engine is cold.
Recent works include new battery, terminals, valve cover gaskets, PCVs clean up, air filter, oil change all one week ago.
About 3 weeks ago while driving it, got the code for MAF sensor. Managed to get home, cleaned it, cleared code and everything back to normal.
6 months ago replaced all CATs, A/F sensors, heated sensors, full suspension (shocks, links, steering rods, etc). also had timing chain work done as well.
It has always run strong, now its acting weird.
No Infiniti/Nissan dealer nearby so trying to troubleshoot from home as much as possible.
Thanks again!
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dougracezs

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Hi, having this same issue. I am also showing codes P0172, P0175, P0133 in addition to P062B. Going to start with the basics; battery looking for cut wires in the harness and then go on from there. Thanks for all the info you guys have provided.
Intake valves get clogged due to the direct injection. The loss of air flow confuses the computer which causes it to lean out and/or richen up. the computer doesn't get the mixture reading it thinks it should see at the air/fuel sensor. it will continue to try to fix the problem by continually adjusting the mixture ratio. eventually the ecu gives up and goes into limp mode and usually throws a ecm code p062b and an air fuel code for one or both banks. at this point the ecu gets "locked" and will run poorly until it is reset. First, remove intake plenum and check/clean intake valves. this seems to be the true fix. disconnecting the battery doesnt seem to reset it. After cleaning the intake valves, try to disconnect ecu completely and the reconnect after being disconnected for 15 minutes.
 

mmwhite8075

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Intake valves get clogged due to the direct injection. The loss of air flow confuses the computer which causes it to lean out and/or richen up. the computer doesn't get the mixture reading it thinks it should see at the air/fuel sensor. it will continue to try to fix the problem by continually adjusting the mixture ratio. eventually the ecu gives up and goes into limp mode and usually throws a ecm code p062b and an air fuel code for one or both banks. at this point the ecu gets "locked" and will run poorly until it is reset. First, remove intake plenum and check/clean intake valves. this seems to be the true fix. disconnecting the battery doesnt seem to reset it. After cleaning the intake valves, try to disconnect ecu completely and the reconnect after being disconnected for 15 minutes.
Hi Doug,
Thanks for the info. I will get that worked on After I changed the battery out it started okay. Came home and started it immediately after shutting off and it started up fine. I waited 15 mins to start again and it started ran rough for ~10secs and revs to 1200 RPM and then idles smooth. Truck runs okay except for longer shifts.
 

marctronixx

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there is an ecu reset procedure (using the accelerator pedal and key onoff timing dance) that can also clear out drive patterns and data points the ecu learned over time. ive done this many times on my armadas and qx over the years to regain that low end, reset shift points in the trannt, etc. old school procedure.
 

M I Z

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Hello Gents,

Just wanted to update you on my troubleshooting journey.

Unplugged ECU and battery. Cleaned ECU plugs and terminals with electrical cleaner. Let it sit for 24hrs and reconnected everything. Car starts with lots of sputtering until it goes into a mode where its accelerated at 800rpm and it runs smooth but I know is not right cause tranny shifts wrong and engine has little power. I get no codes or lights on my dash or with code scanner. Browsing through the internet I have found that it may be fuel pump related?. its still on original pump. I reset the ECU and it goes back to this. Any thoughts?

Thanks in advance!

M.
 
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