2009 Infiniti G37 No Start No Crank Intermittent to Permanent

Douglas Engineer New York Posted   Latest   Edited  
Resolved
Electrical
2009 Infiniti G37 X 3.7L (VQ37VHR) 7-spd
No Crank / No Start

I have a 2009 Infiniti G37 AWD, 205,000 miles with what started as an Intermittent No Crank No Start to a Permanent No Crank No Start. When the vehicle would start after an extended time sometimes as short as a couple of hours to as long as a full day the car operated fine with no DTCs – it was actually driven from Buffalo to Rochester after a No Start situation and it made the trip with no driveability issues and no DTCs. 

As a No Crank No Start the only working system was the Automatic Drive Positioner controls – Seat controls and telescoping steering wheel along with the horn and the rear brake lights when pressing on the brakes. I started the Diagnostics as No Crank No start by checking the main fuses, fusible links and worked my way to the secondary fuses and found all fuses to be intact and receiving proper voltage. I checked the ground from the battery post to the engine block and multiple chassis grounds and found no voltage drop however this was not a loaded system as I had no power when pushing the ignition switch.

I continued to follow the steps of what is required when the push button ignition switch is pressed inside the vehicle. Step 1 after pressing the Push Button Switch the BCM activates the inside key antenna and transmits the request signal to the intelligent key (key fob). I checked and the BCM is seeing the Push button signal when pushed but there is no signal sent out from the BCM to the inside key antenna. To add to this I verified that there is no signal when the intelligent key is in the passenger compartment or when it is outside the passenger compartment and for both cases there should be 15Volt spikes on a regular basis which is not present. I tried both key fobs and replaced batteries in both key fobs. I tried placing the intelligent key in the key slot (security system backup if your key fob goes dead to start the car) and no change. 

From this information I zeroed into the Powers and Grounds on the BCM and they all checked out okay. I’m ready to call a BCM here but this involves a new BCM and reprogram which I don’t have the capabilities to do. I did a quick check on the CAN system and saw 60 ohms at the BCM which validates the terminating resistors are intact in the IPDM and the ECM. The CAN signals are showing minimal voltage (0.6 V) on both CAN high and CAN Low but I assume that is because the ignition power cannot be turned on? For those of you familiar with Infiniti/Nissan please let me know if I should be doing additional checks and if this problem has been seen before. 

Is a faulty BCM the right call? Thanks for your help.

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Sean Owner/Technician
California
Sean
 

Steering gear lock comes to mind on some nissans that had similar problems..just my 1 cent in, hope others chime in..

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Matthew Mobile Technician
Japan
Matthew
 

No codes in the BCM? These are notorious for the steering lock breaking, which sets a B2607 along with other codes that will take you down a rabbit hole that leads to replacing a perfectly find BCM. The fail safe for this code is to inhibit cranking.

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Douglas Engineer
New York
Douglas
 

Matt without power to the ignition I don't have any communication to the BCM or any of the other modules accept the Automatic Positioner Unit that still enables power to the seat and telescoping wheel. I do have power to the DLC and by keying in the VIN on my Autel scanner I can communicate only to the Automatic Positioner Unit. Is it possible that I am missing a CAN communication problem? I…

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Richard Technician
New York
Richard
 

Try putting the hazard lights on and see if you can communicate with any more modules. I recall having this issue a few years ago and it was the steering lock module. I was able to communicate when the hazards were on.

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Douglas Engineer
New York
Douglas
 

Richard the hazards are not operational. I should also point out the interior room lamps do not come on when the passenger or driver side door is opened. I did check that the switch for the room lamps is enabled for this operation. I did check again what my scanner can communicate with the ignition switch in the OFF position (unpressed) and the Automatic Driver Positioner is the only unit…

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Douglas Engineer
New York
Douglas
 

Thanks Sean I was thinking the same thing but that step of the BCM transmitting the Steering Lock unlock signal to the steering lock unit and the IPDM falls further down the chain of events. It appears that the earlier step involving the intelligent key is not happening. Nonetheless I had planned on disabling the steering lock unit the next time the car had power to test the steering lock theory…

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Caleb Diagnostician
Indiana
Caleb
 

Have you looked at the CAN on a scope? That way you could see if its trying to do something or not. Put a signal generator in the CAN an see if it gets pulled down. Let the car go to sleep while monitoring the CAN bus. Then "wake it up" by opening the door, attempting to start the car etc and see if there are any changes to the waveform. Let us know the results. I believe airbag modules an the…

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Caleb Diagnostician
Indiana
Caleb
   

I just reread your post. I am confused. You said the CAN had .6 volts on it but you can communicate with the BCM. Thats not possible.

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Douglas Engineer
New York
Douglas
 

Caleb I put a scope on the CAN signals and I'm not seeing any activity I am not getting any reaction from opening the doors or pushing the ignition button so it appears the car does not awake. What I see on CAN H and CAN L is a constant .6 Volts no activity with my scope. I mentioned earlier in this condition my scanner only identifies the Automatic Drive Positioner unit. I am seeing 60 ohms on…

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Caleb Diagnostician
Indiana
Caleb
 

Thank, yes helps a little. However you said the BCM is seeing the push button being pushed. How did you arrive at that this conclusion?

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Douglas Engineer
New York
Douglas
 

I back-probed pin 89 on a BCM connector which receives the input from the Push button ignition switch and validated that it sees 12 volts when not pressed and 0V when it is pressed

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Caleb Diagnostician
Indiana
Caleb
 

Thank you! Yes that helps alot! I thought you were viewing data in the BCM thru the scanner. I personally would chase a CAN issue at this point. If the CAN is really always stuck at 0.6 volts that is not correct. It should eventually fall asleep and go to 0.0 volts. I know you have 60 ohms but have you checked pins 6 an 14 to ground to see if you have any continuity? Can also stick a signal…

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Douglas Engineer
New York
Douglas
 

Thanks Caleb I will check tomorrow if my CAN signals are shorted to ground.

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Matthew Mobile Technician
Japan
Matthew
 

OK, it looks like the BCM isn't waking up, even with input from the start switch. Only problem I have before calling it is the CAN issue. There are other players there, and it "feels" like there should be activity there. I'd take the BCM off the network, and see if anything comes alive. Worried that something may be pulling the whole thing down. But no comm codes...

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Victor Owner/Technician
Florida
Victor
 

Or maybe pull fuses one at time until communication is restored.

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Douglas Engineer
New York
Douglas
 

Matt, What confuses me from a CAN communication perspective is what should I expect if I can't get the system into a normal key on engine not running condition. Since the ignition system is not moving from the key off position maybe the CAN communication I am seeing is normal. I will take the BCM off the network tomorrow and report back - Thanks

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Caleb Diagnostician
Indiana
Caleb
 

I think your CAN is shorted even if it's a high resistance short. CAN should be active as soon as you open a door.

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Caleb Diagnostician
Indiana
Caleb
   

After looking at a schematic the car only has 2 networks. The CAN on 6 and 14 and a K-line on pin 7. Is there any activity on pin 7 when attempting to start the car? The K-line should have 0-12 volt square wave. On this car the ECM, TCM, and ABS are the only ones on the K-line. Please check that as well. Also when you talk about 15 volt spikes you are talking about the low frequency antenna…

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Douglas Engineer
New York
Douglas
 

Caleb I will check the CAN lines 6 and 14 for short and I will check pin 7 for activity tomorrow. And yes I was talking about the low frequency antenna circuits showing no activity (dead) as well which is required for the BCM to transmit a request signal to the intelligent key after the ignition switch is pressed.

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Caleb Diagnostician
Indiana
Caleb
 

Cool thanks. Sorry I keep adding to my post lol.

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Douglas Engineer
New York
Douglas
 

Caleb no problem with the questions , keep them coming it helps me to think more about the entire system. Well I was able to check pins 6 and 14 today for a short and it does seem that there is a problem here. With the battery disconnected I was getting about 850 ohms on both pins 6 and pin 14 when I connected them to ground. So it doesn't appear to be a full short but a partial with some…

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Caleb Diagnostician
Indiana
Caleb
 

Thanks for the feedback. I would not get hung up on the resistance. If you are concerned about the 850 ohms I would just compare it to another car with a 6&14 Powertrain CAN network. I would reconnect the battery and start unplugging modules on at a time. Starting with ones that share CAN and the K-line and see if anything changes on the scope on either network. If you cant get a change you…

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Douglas Engineer
New York
Douglas
 

Caleb - Thanks for the ideas I will continue my hunt

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Victor Owner/Technician
Florida
Victor
 

There should exist a healthy 12volts on pin 7 KOEO.

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Douglas Engineer
New York
Douglas
 

Victor I did check out pin 7 with the current state I'm in which is no change in power status at the push button ignition (it does not move from the OFF position). I read a steady 1.78Volts on pin 7

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Victor Owner/Technician
Florida
Victor
 

That reading suggest that the K line is shorted to ground somewhere​.​Pull connection to module until a reading of 3volts or better is obtained​.​IIRC this is a J1942 protocol. ABS; ECM;BCM;ABS

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Douglas Engineer
New York
Douglas
 

Victor looking through the CAN system for this car I only see a High Speed CAN Bus attaching all the modules except one UART communication between the Driver Seat Control Unit (which is on the High Speed CAN Bus) and the Automatic Drive Positioner Control Unit (Not on the High Speed CAN Bus)

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Michael Technician
North Carolina
Michael
   

Douglas if you could do me a favor and try a weird procedure I’ve ran across in the field. If you could try hitting the push button while pressing the brake pedal and holding the shifter detent button with the key in the vehicle. On multiple vehicles with ecu can com issues I’ve found that it will turn the ignition on without some signals from the ipdm or ecu. Unfortunately I’ve never tried it…

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Douglas Engineer
New York
Douglas
 

Michael I gave this a try today with no success. I did try it with the intelligent key in the key slot as well. I actually pulled out the sun roof drain to take a closer look because there did appear to be some leakage into the passenger side foot well area (some moisture on rug). I updated the drain with a hose extension and made sure it was clear and reinstalled so thanks for the tip on that…

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Michael Technician
North Carolina
Michael
 

Does this unit have an icc sensor by chance?

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Douglas Engineer
New York
Douglas
 

Mike it does not have an icc sensor

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Michael Technician
North Carolina
Michael
 

I’m going to say at this point if you have no shorts to ground, (I’d say no need to check for shorts to power due to low voltage. Your bums first signal to wake up should be the door switch. The hazards are also controlled by the bcm as previously mentioned. If I’m not mistaken the push button signal should reach the bcm as you verified, from there the bcm should request the ipdm to turn on the…

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Douglas Engineer
New York
Douglas
 

Thanks Mike - I put this aside for a couple of days but your suggestion with activating the ignition relay may be required to troubleshoot further. I believe there are two ignition relays in this system one in the fuse box and another in the IPDM so I'll have to check out the chain of events and what is required. Caleb provided a starting sequence which maps the sequence which should be helpful…

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Douglas Engineer
New York
Douglas
 

Sorry for the long delay the customer was not in a rush on this vehicle and I knew it was going to need additional time. Mike I verified the CAN system and did not find any shorts (to Bat+, ground or each other). I am satisfied this is not a CAN communication issue. The system did fire up by chance and operated for a short time and I was able to verify the 0.6 volt CAN reading with the ignition…

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Michael Technician
North Carolina
Michael
 

Douglas I would never say this at work but i have the launch x431 diugan and it is able to do both read and write functions for new modules as well as program keys for that year all the way up to 2016 for sure. Used bcm as are also an option if you’re trying to avoid programming but will still require key reprogramming (please make sure it’s from the same model, auto or manual, with same…

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Douglas Engineer
New York
Douglas
 

Mike you have me intrigued but I'm new to this programming and module swap world. A couple of additional questions if you don't mind: 1) If I go the Used BCM option and I match all the car features along with module part # exactly would the only need be the key programming to finalize swap? 2) If I go the used BCM option and don't have all the same features but the same module part# would I be…

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Douglas Engineer
New York
Douglas
 

Mike just wanted to add to my reply below - If I can get matching BCM part numbers but not matching vehicle equipment can the used BCM be coded to match properly? If yes can this be done by the x431 diugan? Two BCM pictures attached original and used.

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Michael Technician
North Carolina
Michael
 

If the part numbers match exactly it’s from the same exact vehicle. As far as I know a bcm can only be configured once with the Nissan scan tool. But it also only needs to be done once. You should be able to plug it back in but will still need to register the key fobs in the bcm. The bcm checks the id that is stored in the ecm and bcm and makes sure they match. If I’m not mistaken you’ll get a…

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Caleb Diagnostician
Indiana
Caleb
   

Nice work man. I think you have more than covered your bases. You can you use alot of decent aftermarket scanners to set up a used BCM in that vehicle I believe. Or if you want to try to repair it you could try this guy, he seems quite knowledgeable. He also has a YouTube channel. google​.​com/url?sa=t&s…

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Douglas Engineer
New York
Douglas
 

Caleb I appreciate your help here and I'm weighing out my options going forward, see my questions to Mike. Again I appreciate all your help and feedback just looking forward to getting that car back on the road.

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Douglas Engineer
New York
Douglas Resolution
 

All - It has been a long time coming for the resolution to this issue. The BCM was the issue on this car as first thought. The fix was a used BCM with the same manufacturing part number but not necessarily a car with all the same options. Even better the Launch x431 Diagun V scanner was successful in getting the ECM to recognize the used BCM which was followed up by the successful reregistration…

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Helpful
Thanks
Michael Technician
North Carolina
Michael
 

That’s awesome. Glad you got it! That’s actually a common concern that happens to me with the PIN numbers even when using the oem consult tool. I also have the x431 too and love it!

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