camb003

2010 G37S Coupe with 108K miles. Initial codes P006A, P0101, and P0175 using Innova 3100i OBD computer. Confirmed codes 2 days later with OBDLinkMX+ using OBD Fusion - report attached.

Innova 3100i also diagnosed Charging System Voltage PID 13.25V "Charging Voltage is below the acceptable limit". Need to look into finding this via OBDLinkMX+, still learning how to use it.

Initially cleaned TB's/MAF/MAP sensors and replaced air filters. Applied all 3 relearn procedures several times.

Symptoms persist: can't hold idle for too long, car shuts off at times when park idling but after restarting is runs fine for a while. It starts ok again and sounds good, runs for a while then begins misfiring and hesitating like the limp mode when driving.
At this point with no engine light coming it feels as if car did not learn idle. What next?!

OBD Fusion also revealed other codes: P0725, U1000. Read some postings on those, speed sensor issues.

Previous work: Replaced A/T fluid at 104K (https://www.myg37.com/forums/d-i-y-i...rop-clean.html), did not dropped the pan but did the procedure 3 times and car ran great with better response shifting. I change oil, filters, coolant, serpentine belt, ATF and Diff fluid at prescribed intervals.

MAF sensors readings seem right, at 0.29 and 0.41 lb/min. (I have a sensor on the way to replace). Short term fuel % trims on Bank 1 and 2 at -15.62 and -17.19 don't seem right and would explain the hesitation and jerking. But what is causing this?

I'm thinking anything below is possible. Am I on the right track here? Do you see anything I'm not seeing? Have you had something similar or have a suggestion?

MAP sensor?
Idle relearning?
Air hose leak?
Alternator going bad?
ATF, wiring around pan?
Reprogramming Engine Control Module via SB ITB12-026a? I've had the car for over 2 years and never had a problem other than cleaning TB's.
Gallery gasket?

Thanks!

SonicVQ

First of all, EXCELLENT presentation of your issues and what you have done. HUGE bonus points for posting the OBDFusion Diagnostic report - that was very helpful.

My thoughts:
• Don't worry about the "Charging Voltage is below the acceptable limit".
The G37s charging system has "variable control" and the voltage can be as low at 12.8 volts after 4-5 minutes of engine run time.

• Your fuels trims are out of range.
At idle, 15-17% of the fuel is being removed. If you haven't cleaned them with a MAF cleaner, please do that. When they get dirty the under report air flow at low engine load, then over report at high engine load.

• MAF A / MAF B differences should be closer. Typically within 0.1 - 0.2 lbs/min. Maybe a MAF cleaning will help. Also, check the PCV hoses and "black blocks" for cracks.

• The MAP sensor is fine. You never need to clean MAP sensor, dirt/oil doesn't change the pressure.

• Yes, you need the ITB12-026a. Your ECU ID is 1NG2A and is listed in the "table A" / TSB applies to section.
The latest version for your ECU is 1NB4A and I suspect they will update you to that.

• The P0725 can be caused by a problem on the CAN bus (car's network)

• Speaking of the CAN bus, the "intelligent master" (aka Audio/Video module) and the body control module has BOTH reported CAN bus issues. This might be related to the P0725.


Summary:
• Clean your MAFs
• Clear all the trouble codes from all modules, so we don't see any old codes that may not apply.
• Get the TSB done.
• Drive the car for a few days, and scan it for codes to see what is going on.

Good Luck!

camb003

Thank you, I appreciate your input.

• MAF sensors couldn't be any cleaner at this point. Bank 1 sensor is brand new (old sensor at Bank 1 was 1 year old) and have another sensor coming in today for Bank 2. These I purchased 3rd party from amazon. As far as readings are within specs I'll go with that. These are $309 a piece from local dealer, so will cross that bridge later if I have to. I know many vouch here for OEM. Is there a visual way to tell the difference between an OEM vs 3rd party MAF sensor? Sealing gasket any different?
• Cleared trouble codes yesterday, relearn procedures, ran for a while, and took another hit, report attached. MIL On with the same 2 codes confirmed. This one also includes Freeze Frames.
• SB ITB12-026d scheduled for Monday 1st thing, $200 seems to be the going rate in NorCal. (d - includes QX56 models but I'm sure is the same as ITB12-026a for my vehicle).
• Off to disconnect hoses and see if I find any issues with hoses at PCV and black blocks. From Technical Manual EC-518 Positive Cranking Ventilation Component Inspection 1. Check PCV Valve - "With engine running at idle, remove PCV valve from rocker cover. A properly working valve makes a hissing noise as air passes through it. A strong vacuum should be felt immediately when a finger is placed over valve inlet." Are they suggesting to use a 23mm wrench and remove PCV from threaded end and feel vaccum created by intake manifold sucking air? Wouldn't it be easier to shake PCV and make sure it's not stuck? Clean it?
• One last thing I didn't mention. When this happened 3 days ago or so I ended up buying new WIC air filters since K&N were pretty dirty. I don't think this would make a significant difference until I can get around cleaning K&N but wanted to cover all potential issues.

camb003

• Inspected PCV hoses on both banks and were OK.
• Inspected coolant level. Last time I checked it was topped off but not this time. Suspected low.
• Installed new MAF sensor that came in today on Bank 2. (2 new sensors now).
• Ran all 3 relearn procedures, no hesitation, jerking or stalls during procedures and after 5 miles.
• Went to get a gallon of blue 50/50 to top off tomorrow. Began monitoring and noticed engine coolant temperature rising to 190 then 200. On highway down to 185 then rise to 190 when idle at stop light 200. Car coolant temp gauge would go up slightly but never above middle mark.
• Could this high engine/coolant temperatures be the culprit of those other Cel Codes related to CAN COMM and Speed Sensor? Doesn't water cooling also goes to AT on this vehicle?
• Came home and parked and noticed both fans were off with car idling.

My suspicion of a coolant leak have gone high now for 2 reasons. Over the last few months at least on 2 occasions I was noticing a little puddle of water collecting below passenger side door right by the front windshield. I touch with my finger and smelled it but I thought it was the AC. As I was reading postings on what could cause high coolant temperature I read a posting were someone describes having a coolant leak exactly where I've been seeing it. It kind of makes sense now that being diluted 50/50 it didn't have a strong coolant smell. I would not be surprised if this gremlin, at least for P006A, P0101 codes, was caused by high engine temperatures due to a coolant leak. I mean at some point air inlet temp was 132 F.

Seems like I have to find out how to bring those radiator fans back online and find a potential coolant leak, probably by the end of the engine on the firewall by the passenger side. For a moment I thought this could this be a water pump failing? But later I read these water pumps last a long time. Or equally taxing the galley gasket?

I've attached OBD Reports after replacing MAF sensor on Bank 2 and driving 5 miles (P0175 reported), and after clearing it and ready to drive again tomorrow.

I'm also getting the SB done Monday morning at local dealership. In conversation with Service Writer I could sense that tone like "we have never seen your car at an Infiniti Dealership for service" and "we can't guarantee that after reprogramming your car will have new software", "We will still charge you $200 even if it does not update". What?!!! I kept my cool and simply said I've already confirmed via Infiniti Service Bulletin ITB12-026d and my OBD scanning that my car needs an update and Infiniti SB states so. What are the chances these "20 yrs experience Infiniti Techs" don't actually have the latest software in that Consult III to reprogram my current ECM with a 23710-ING2A number? She, the service writer, does not know anything about this SB. So I feel like talking to the mechanic on Monday and if he can't guarantee he can drop the latest software in my ECM (1NB4A?) I should simply walk away and go to another dealer. BTW will this new ECM number a "random" number? That's what the service writers are calling it. I would venture to say there is nothing random about a software update number but it would reflect the latest Infiniti ECM software update from June 6, 2013, the date this SB was released.

As usual your feedback and experience is welcomed. Does it sound like I'm on the right track here?

camb003

• Topped off radiator with about a cup this morning. So now doubt I have a serious leak.
• Warmed car this morning, turned A/C on and fans came on so nothing wrong with fans or fan control module. Aren't cooling fans suppose to come on at idle when engine reaches a certain temp?
• Had a friend revved car at 3,000 RPM and after about 5 minutes felt lower coolant hose water flowing so my thermostat seems to be opening.

Is there a way to check that temperature sensor besides replacing it.

I'm thinking replace coolant or flush the system.

Any thoughts or ideas?

Picture attached while revving to check thermostat opening.

SonicVQ

Good progres!!!

My thoughts:
• Your coolant temps are in the normal range & high coolant temps don't cause CAN bus / speed sensor issues.
• The cooling system fans are fine, if they come on when the A/C is on all is good.
• The MAF issue seems to be fixed. The last 3 diagnostic reports didn't have the engine running, could you post one with the engine at idle after a 5 minute drive / or report the MAF A and MAF B.
I want to verify that they are almost the same value.

After Monday, the remaining issue is the P0725.

The factory shop manual states that the P0725 detected if:
• TCM does not receive the CAN communication signal from the ECM.
• The engine speed is more less 150 rpm even if the vehicle speed is more than 10 km/ h (7 MPH).


You might want to head over to nico club and download the factory service manual (free!)
As for troubleshooting the P0725, there are not many checks before it says to replace the control valve body & TCM ($$$$$)

After the ECU is updated, drive the car for a while and check it for codes.
Good luck on Monday.

camb003

• 2 ea. Diagnostic Reports and 1 ea. picture attached.
• Diagnostic Report # 1 going on highway at 61 MPH. MAF look very close at 2.73 and 2.67. Catalyst temperatures Bank 1 and 2 Sensor 1 at 939 F?! This doesn't sound right. P0725 did not come back but P0171 shows up as a new code.
• From FSM: P0171 DTC detecting condition • The amount of mixture ratio compensation is too large. (The mixture ratio is too lean.
• From FSM: P0171 Possible causes: Intake air leaks • A/F sensor 1 • Fuel injector • Exhaust gas leaks • Incorrect fuel pressure • Lack of fuel • Mass air flow sensor • Incorrect PCV hose connection. Just because all other codes went away this makes me wonder if my problem is the MAF sensors since mine are 3rd party.
• Dianostic Report #2 coming on highway at 67 MPH. MAF look very close at 2.15 and 2.12. Catalyst temperatures Bank 1 and 2 Sentor 1 at 1004 degrees F?! No trouble codes (nor P0725 nor P0171) reported coming back home on highway!
• Picture with car parked and idling after coming back shows RPM's at 750 with ATF Temperature 1 at 177.8 degrees Fahrenheit (Transmission) and Engine Temperature at 201.2 degrees Fahrenheit. Isn't this too high?

SonicVQ

• The catalytic converter temperatures are in the normal range.
They are calculated (not measured) based on engine load and can be as high as 870C / 1600F. My typical highway temps are 580C / 1076F... Nothing to worry about here

• Glad to hear about the P0725 not coming back... Hope it stays that way

• The ATF temperature is also normal. The ideal operating temperature for automatic transmission fluid is between 175 and 225 degrees. At approximately 240 degrees, important additives in automatic transmission fluid (ATF) begin to cook. (https://www.motortrend.com/how-to/08...smission-tips/) I can't give you my typical ATF temps, as I have the 6 speed manual.

• The engine temperature is also normal. Don't let the gauge trick you into thinking 220F is in the dangerous "red zone". On a hot day (33C / 91F) my coolant temp will hover around 94C / 201F after exiting the highway and coming to a stop. On a 3 hour drive, the hottest temp recorded was 96C / 205F

In looking at the last diagnostic report, everything looks good. BUT time will tell

camb003

This is good to hear. Is there any reason why they would not want to update the Engine Control Module to 1NB4A from my current 1NG2A? When I talked to service writers on the phone last week they mention part number after reprogramming was a "random" number. I find that hard to believe but then again the mechanic takes care of that. I'm just a tad concern she mentioned that if it doesn't get updated I will still get charge $200.

SonicVQ

The EDU ID is not a random number, but it does look like one.
The EDU ID is the same for a given G37 based on year and options.
Here is a list to prove my point: https://uprev.com/romlist.php

As for the hesitation to install the update, I think some shops get worried about the update failing and then having to spend time to fix it.

You could cancel your appointment and see if the P0106 comes back.
Then with the code in the ECU, point out the TSB and try again.

camb003

• Drove to dealer, no trouble codes logged.
• Changed my mind about reprogramming ECM until P0106 comes back.
• Came from dealer, no trouble codes logged, 100 miles driven since no trouble codes reported.
• Noticed my idle RPM hovers around 700-725 now vs 675 before this round of codes started a few days ago.
• Early to tell but it seems like replacing MAF's and relearn procedures fixed it for now.
• Crossed my mind if this could have been bad gas from Costco?

Thanks for sharing rom list! That's what I thought, these couldn't be "random numbers". So I take it 2 rom files. 1 to upgrade to latest rom (for my vehicle 1NB4A) and 1 to fallback to stock rom in case something goes wrong (for my vehicle 1NG2A). Come to think I should have asked if they could fallback to stock rom. Are both these files in CONSULT-III?

Appreciate your insights, and yes time will tell.

SonicVQ

Those ROM files are encrypted and will only work with the UpRev tuning software.
The link to them was just to show how the ECU IDs are related to year, model, etc.

Bad gas is possible, but if your Costco gasbar is as busy as the one around me, I don't think it was the gas.
When you replaced the MAF, the airflow values were much closer to each other and I think that was the root cause of the "too lean code"

You are welcome and enjoy your G37... it just may be the best car Infiniti ever made.

camb003

• All today
• 3 OBD Reports attached and FSM DTC/CIRCUIT DIAGNOSIS
• Report #1 Idle after work (P0174 Pending). Noticed idle RPM higher around 775 then sag to 675 for about 4 seconds then jumped to 775 again.
• Report #2 At 83 MPH on highway (P0171 Pending)
• Report #3 Idle after coming back from highway (P0171 Pending). Same observations as #1 above.
• Observations worth mentioning from expected sensor parameters after watching video below "G37 All Engine Sensors Explained" and looking at my OBDFusion Reports:
• Fuel Trims for each Bank should be between -10 to +10 %. After adding mine. Report #1 at Idle is ok at 2.34 for Bank 1 and 0.78 % for Bank 2, but Reports #2 @ 83 MPH on highway is at 26 % for Bank 1 and 18% for Bank 2, Report #3 at Idle is at 35 % for Bank 1 and 35% for Bank 2.
• Ignition timing advance for #1 Cylinder should be about 10 degrees @ hot idle. Mine show report #1 at Idle 1 degree and report #3 at idle at 0 degrees. Not sure if this is significant but worth mentioning since it's not what video shows. Report #2 at 83 MPH is 50 degrees
• Intake Air Temperature (at MAF Bank 1 only) is suppose to be around 133 F or (55 C). Reports #1 and 3 are 149 F and 142 F respectively but when at 83 MPH on Highway Report #2 is 90 F. Less temperature = less voltage = lean? Not sure but worth asking.
• Absolute Throttle position. Clean TB would be around 1% (mine look OK at 1.18 Report #1 and 1.57 Report #3), dirty TB would be around 2%, Max Throttle Body would be about 88%. My car going at 83 MPH shows this value at 6.27 % in Report #2. Is this OK?
• Commanded Actuator Throttle Control would be the same as Absolute throttle Position B and Absolute Throttle Position. This is the case for Report #1 and #3 during idle but not for Report #3 where Absolute Throttle Position should be 4.71 but it's 6.27. Do these values show anything to be concerned about?
• Although I wonder a bit about the 3rd party MAF sensors I purchased I must say MAF parameters reported by OBD Fusion and Infiniti FSM Service Data Specs for Mass Air Flow Sensor per EC-623 are dead on spot by Infiniti Specs.
• Per FSM for P0171, P0174 here is the Detecting Condition: Fuel injection system does not operate properly. • The amount of mixture ratio compensation is too large. (The mixture ratio is too lean).
• Per FSM here are the possible causes: • Intake air leaks • A/F sensor 1 • Fuel injector • Exhaust gas leaks • Incorrect fuel pressure • Lack of fuel • Mass air flow sensor • Incorrect PCV hose connection.

I do remember the PCV hose connection was easy to pull at the top (like I could pull it with my hand on bank 2. I didn't think this was a big deal since is not loose (lateral play) but I suppose I could buy these hoses and clamps, maybe even replace the PCV's as well just to eliminate this as a possible culprit.

Any thoughts? Thanks.

Mine are more like:
1. Keep driving car and see what it does.
2. Keep looking for intake air leaks.
3. Have a shop jack the car and feel for exhaust leaks ($).
4. Buy new OEM MAF sensors ($$).
5. Reprogram ECM ($) (I called another Infiniti dealer and inquired about reprogramming. They'll do it for $200. I asked and he said they don't go back to stock reprogramming if anything fails).

Nissan & Infiniti 3.7 litre V6, All Engine Sensors Explained: OBD4Everyone Ep.18

https://www.youtube.com/watch?v=CXDX-89_ArU

camb003

Found this on Nico Forum posting.

"Then the p0171 code was still coming up, so did a search and sprayed carb cleaner all over motor,power brake booster and all...nothing...then I noticed the pvc hose was all wet with oily residue...went to take it off(hard as a rock), and it spun real easy on nipple coming off the intake manifold-turns out it was split underneath where you could not see it and carb cleaner did not get to it....replaced the hose...and voila! cured that code too...gas mileage went up a couple miles per gallon too..I was at 16, now about 19!! still not 30 like I want, but hey i do drive it fairly hard, and sort of fast...so I guess any improvement is good...."

camb003

• Swapped MAF's yesterday morning and clear codes with OBD Fusion to see if P0701 would move to bank 2 and show as P0704.
• Drove to work and back yesterday and no codes came back but idle was still rough at 750 and felt a bit rough driving on the highway.
• Performed all 3 relearning procedures this morning cold and RPM's are now back at 650 and car drives and feels as it use to.
• Last OBD Report on the highway attached. Trims and MAF's numbers look good as far as I can tell.
• My 2 cents about MAF sensors below
• Replace or clean them as needed with https://www.crcindustries.com/produc...-11-wt-oz.html
• Relearn procedure per
  You Tube
• Do not over tighten MAF sensor screws (Per FSM 13 inch lbs) Is a CONSULT III OR GSM worth the cost to troubleshoot G37?

I hope this will be it for this round and I can really keep enjoying probably the best car Infiniti ever made.

Thanks. Your insights are always appreciated.