2012 QX56 - P062B code - Sputtering and loss of power

rbmphillips

New member
8
1
0
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.
 

marctronixx

Staff member
1,457
52
48
Los Angeles
the parts are not expensive, its the labor.

that code is a serious code. that code corresponds to fuel system, injectors, ECM, TCM, Crank and camshaft sensors, MAF, O2 sensor in the manifold. the fact they narrowed it down to those two things is a good sign though, as it could be much worse.

the code mainly means there is a voltage issue/short, causing the injectors to not spray fuel into the chamber properly under a given load. when you press on the accelerator, or go up a hill, naturally the engine has to work hards to perform in those instances, and a more stronger fuel pulse is needed to put more fuel into the chamber. if there is a continuity issue with a wire harness for example, that fuel may not get into the engine when the engine needs it, causing sputtering and bogging down of the engine.

as an aside, have you had the battery/alternator checked? if the battery is weak or the alternator, this can also cause an issue.

when you say "recently just purchased", how recent? did you purchase CPO or from a 3rd party/private party?

do you have the service records for the car? was the car qualified for the recall on the timing chain?

im sure the code has happened to some people before--its not just to nissan but to many others cars that have an electronic fuel delivery system.

if you are handy, you may be able to replace the parts yourself. The wiring harness, depending on which harness specifically, could be a nightmare because it may involve removing the dash and/or interior panels to access the full harness.

again its the labor--the parts are probably less than 1000 dollars USD.
 

primov8

Active member
110
76
28
NYC
The ECM and ECM harness connectors are located right next to the battery.

Remove the battery and battery tray so you'll have access to the ECM protective plate and more room to the ECM harness connectors. The negative battery cable grounds to the chassis located under the battery tray so check that as well. Disconnect, inspect the pins and clean the ECM harness connectors using CRC QD electrical cleaner.
 

rbmphillips

New member
8
1
0
The Engine Harness is 3k and the EGI Harness is 1k. Quite expensive. The labor to replace both is 3k as well.
I will check battery voltage tonight but I have a feeling it is ECM or Wire Harnesses or both.
I purchased it from a used car dealership.
The service records show that the timing chain recall has already been completed.
The vehicle was always serviced at a Infiniti dealership and has all service records. Very well maintained.
The Infiniti dealership that I took it to for diagnostics said they have seen a few of these come through that land in my VIN# production cycle that have had issues with faulty Engine / EGI harnesses.
______________________________
 
Last edited:

marctronixx

Staff member
1,457
52
48
Los Angeles
good tips from primo to have a look-see at the harnesses and clean if needed.

ive not seen that code mentioned for this particular car and i troll 3 dedicated qx56 forums, so its not totally something that's common.

keep the class updated.
 

rbmphillips

New member
8
1
0
I spoke with another knowledgeable Nissan technician this past Friday. He told me to check the battery for corrosion and load test the battery. He said that low battery voltage could be the culprit. ECM could be seeing a dip in voltage and causing the injector drivers to fault because of that voltage dip. I took the vehicle to O'Reillys and had the battery load tested. It tested good but it is the original battery still in the vehicle. Battery is 6.5 years old. The battery posts & connectors were corroded. I cleaned the posts and cable connectors thoroughly and reset SES light. The SES light has not came back on yet but we have driven it much this weekend either. I will wait to see what happens this week and report back. I really hope the corroded posts was the issue but I'm not too optimistic about it.
 

marctronixx

Staff member
1,457
52
48
Los Angeles
Good news bro.

That’s whats I originally stated in my first post, that it could be a voltage issue and that testing the battery/alternator was an easy place to start.

I’d still have a look at those harnesses though, since the first tech seemed to feel there may have been something amiss there....
 

rbmphillips

New member
8
1
0
Im going to take the battery out and clean the ECM harness connection tonight with the CRC cleaner. I am praying that this is the issue. I really do not want to pay 7-8k to fix this vehicle. It is a nice ride but man that's a lot of dinero.

What are the other QX56 forums that you know of?
______________________________
 

rbmphillips

New member
8
1
0
Cleaned the battery, cleaned the ECM conncetions, SES light come back on yesterday. Loss of power going up hills. What kind of symptoms does a bad catalytic converter give?
 
Cleaned the battery, cleaned the ECM conncetions, SES light come back on yesterday. Loss of power going up hills. What kind of symptoms does a bad catalytic converter give?

Cleaned battery, but didn't change it out for a new one? 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.

Bad cats would give bad gas mileage, and I'm sure the cat related codes would be thrown.

Later,
pjdavep
 

rbmphillips

New member
8
1
0
The battery tested good and passed the battery load test.
The vehicle is at the dealership now. Im getting a 2nd opinion about it all. Hard for me to believe that both harnesses and the ECM are all bad.
______________________________
 

ChesbayQX56

New member
15
1
0
I had a similar problem with my 2013 QX56. I was getting some crazy ECM codes because the volts were low. The battery checked out Ok so I started to monitor the volts with the gauge and a live/bluetooth OBDII app. The alternator was constantly turning off and never fully charging my battery. The dealer acknowledge the problem and did something with the idle that helped a little.
Ultimately, I leave the headlights on which always keeps my volts at 13.7. I would recommend that you look at the volts gauge when it starts and then after 3-4 minutes of driving. If the volts drop way down, trying turning on the headlights.
 

rbmphillips

New member
8
1
0
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.
 

Keketd

New member
5
0
1
New Mexic
Cost of Repair?

I'm having the exact problem and I replaced my ECU and the code P062B came back again. Do you happen to know what part number it was that you replaced and the cost of the repair?
 

jstark

New member
4
0
1
Minneapolis
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.[/QUOTE]

Hey RBM, can you disclose specifics, like parts used and/or snap a pic or two of the Catalytic converter modification?

Thanks!
______________________________
 

rbmphillips

New member
8
1
0
I'm having the exact problem and I replaced my ECU and the code P062B came back again. Do you happen to know what part number it was that you replaced and the cost of the repair?

We replaced the ECM AND EGI Wiring harness.

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.

Hey RBM, can you disclose specifics, like parts used and/or snap a pic or two of the Catalytic converter modification?

Thanks![/QUOTE]

I will upload pics today.

I'm having the exact problem and I replaced my ECU and the code P062B came back again. Do you happen to know what part number it was that you replaced and the cost of the repair?

Did you get yours fixed. My problem returned last night. We replaced ECM and EGI wiring harness and now the problem is back.
 

Keketd

New member
5
0
1
New Mexic
At rbmphillips:
Here is a screen shot of the freeze frame data from my scan tool for the code P062B from my QX56.
Freeze Frame Information

Parameter Description Results
Fuel Sys 1 CL
Fuel Sys 2 CL
Calc Load 52.94 %
ECT 71.60 °F
STFT B1 25.00 %
LTFT B1 4.69 %
STFT B2 25.00 %
LTFT B2 3.13 %
MAP 12.40 inHg
Eng RPM 1212.50
Veh Speed 17.40 mph
Spark Adv 34.00 °
IAT 55.40 °F
MAF 3.44 lb/min
TPS 11.76 %
O2S B1 S2 0.29 V
STFT B1 S2 99.22 %
O2S B2 S2 0.27 V
STFT B2 S2 99.22 %
Run Time 55.00 sec
MIL Dis 0.00 miles
LAMBDA B1 S1 1.17
O2S B1 S1 1.70 V
LAMBDA B2 S1 1.42
O2S B2 S1 1.90 V
Command EVAP 0.00 %
Fuel Level 100.00 %
Warm-up DTC Clr 15.00
Clr Dist 96.31 miles
EVAP_VP 0.00 InH2O
BARO 23.33 inHg
CAT Te 11 32.00 °F
CAT Te 21 32.00 °F
ECU Volts 14.40 V
LOAD Value 38.43 %
EQ Ratio 1.00
Rel TPS 6.27 %
TPS B 11.76 %
ACC Pedal D 16.08 %
ACC Pedal E 16.86 %
Command TAC 12.16 %
MIL Time 0 hrs, 0 min
Clr Time 6 hrs, 28 min
FUEL_TYP GAS
FRP_A_CMD 2094.34 psi
FRP_A 2089.99 psi
FRT_A -40.00 °F
FRP_B_CMD 0.00 psi
FRP_B 0.00 psi
FRT_B -40.00 °F

I'm working now on trying to find if there is a short in the harness (EGI) that is causing the code as indicated on the car service manual. Hopefully I'll be able to locate that short using the power probe and I'll give an update on that if and when I get around to it.

At rbmphillips if you have replaced the ECU and EGI harness it might be one of your sensor connector harness thats causing the issue is my guess.
 

CHRIS85

New member
1
0
0
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.

Exact same thing happened to my wife's 2012 qx56. Thousands of dollars to fix and service manager told me Infiniti knows of the issues but it only happened to a certain number of vehicles and they refuse to open a recall. Of course it happened when we paid it off.
 

Chadhafner

New member
1
0
1
Exact same thing happened to my wife's 2012 qx56. Thousands of dollars to fix and service manager told me Infiniti knows of the issues but it only happened to a certain number of vehicles and they refuse to open a recall. Of course it happened when we paid it off.

How many thousands did it cost you? My wife's 2012 QX56 is doing the same and reading the above posts are making me queezy.
 
Top