Hello all,



New member to myG37 but not new to Infiniti and wanted to say hi and thank you for the forum. I tried searching for this and forgive me if I overlooked: I wanted to see if anyone could confirm if the latest ECU update fixed the the charging issue with the alternator. From what I've read, the alternator is controlled by the ECU(Via IPDM) and only tells the alt to charge battery after a certain amount of time/distance traveled.

Reason I ask is because I drive relatively short distances and have come out to the car not starting on multiple occasions from a dead battery. Battery checks out fine, is full and seems to be operating correctly. Have not checked for parasitic draw as of yet. Car is an 09 journey sedan, premium package.


Thoughts on pulling wire from IPDM??


Thanks

 

There was a TSB issued for '08 and '09 models (I know at least coupe, I would assume sedan too, check with your dealer). TSB number is:
ITB10-010b
They changed out the vent control valve design. Really seems to affect low mileage use of the battery. Had the same issue on mine. Havent had any problems since and they gave me a new battery for it.

 

I did read about that particular TSB. I presumed it was only for the 08 model and was redesigned for the 09 and up models. I'll have to take a further look at it .

 

TSB I looked at mentioned both '08 and '09

 

Since mine is an 09 and I'm the 2nd owner, I doubt they will replace my battery for free. I may just see if the vent valve is the old style and if it is replace it and reset the ECU. Valve costs about 100$ .

 

The problem was not the charging. The alternator charge the battery just fine. No problem there.

Yes. G37 use an intelligent power management system that will stop the charge after the battery get to 14.4V then keep the battery at float voltage of 13.6V.
That's exact the values recommended by the battery manufacturers for sealed lead acid batteries.

If you want to use the "old style" battery charging characteristics and disable the intelligent charging feature, just disconnect the battery current sensor located near the battery, on the battery negative terminal.
Once the sensor disconnected, the car will charge the battery to 14.4V and keep it there while the engine is running. Just like on older cars that use a simple alternator and charging regulator.


The problem was the fuel tank vent valve that was draining the battery while the car was off. But that problem was subject of a TSB and the dealers will fix the valve problem.

 

I may pull the sensor as suggested if the TSB doesn't apply. I feel as though the battery applied to this vehicle is to small for the amount of electronics. The smart charging feature seems like an odd pairing to the small battery. Either way, thanks for the replies guys.

 

The battery size will affect the electronics ONLY when the engine is OFF and electronics are ON.
When the engine is running, the alternator provide the power for all the electronics.
When the engine is ON, the battery work as a buffer between the alternator and the electric loads.
In most cases, the battery size matter only when starting the engine.
A good G37 stock battery have no problem cranking the engine even on coldest days.
Disconnecting the sensor will "top up" the battery little more. But your battery will still get drained if you have a faulty vent valve.

Also grounding kit's have a similar effect with sensor disconnect, because they bypass the battery current sensor.

 

I understand the battery's role in an automotive application, I guess I was more speaking on its reserve capacity. I usually wrench on older vehicles, so when I first saw the battery size it took me by surprise.

 

yeah... i was little surprised too... i saw many cars with 1.5L diesel engine with a battery twice as the G37 battery.
I own 2 G37 cars and the battery never show any weakness on any of them. Maybe if you install some aftermarket audio AMP, you may need a bigger battery to deal with the current spikes generated by the additional AMP. But in stock form, the stock battery make's a good job.

 

I hear you, my other car is a 95 infiniti Q45 that has an audio system. The battery I have in that is 70 lbs. Don't disagree with you on the G battery being capable, just for situations such as this, the battery will discharge quickly. My thinking was with a larger battery this wouldn't be such a issue. I hear they were issuing new/larger batteries as part of the TSB