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I've been out of the scene for quite a while because, quite frankly, my car has been driving great! rarely any issues. I decided to check back in today after discovering that my car is susceptible to the problem described here http://www.infinitig37.com/TSB/1ST34.pdf
I've been having cold start issues as far as I could remember but somehow managed to miss this TSB when I was still under warranty. I've changed the battery and have taken it in to local shops and most things seem to be fine. The battery levels have been noted to be low, needing recharge, but I do tend to drive the car every day (albeit short trips) and multiple 1-2hr drives on the weekend. Nevertheless, my G still struggles to start on a cold start (you can even see the instrument cluster flashing).
If I'm able to get my hands on a vent control value and install it, would I even be able to reprogram the ECM as described in the TSB? The dealership is ask for $150 to simply look at it (not counting for repairs).
Here is what I would do:
(1) After letting the car sit overnight, measure the voltage at the battery. It should be around 12.5 volts if the battery is 80% charged.
(2) If the battery is not 12.5 volts, got for a 1-2 hour drive or put a low amp (1-2) charger on it to get the battery level to 80%
(3) Unplug the vent valve (electrically) and let the car sit all night.
(4) Measure the voltage in the morning
(5) See if the car starts normally
It is my understanding this TSB address an issue where the ECU keeps the vent valve open when the car is off. This can slowly drain the battery.
Their fix is to reduce this current draw by re-programming the ECU and replacing the vent valve with one that operates the same, but at a lower current.
Just changing the vent valve may help a little, but the ECU will still have the old programming.
Here is what I would do:
(1) After letting the car sit overnight, measure the voltage at the battery. It should be around 12.5 volts if the battery is 80% charged.
(2) If the battery is not 12.5 volts, got for a 1-2 hour drive or put a low amp (1-2) charger on it to get the battery level to 80%
(3) Unplug the vent valve (electrically) and let the car sit all night.
(4) Measure the voltage in the morning
(5) See if the car starts normally
It is my understanding this TSB address an issue where the ECU keeps the vent valve open when the car is off. This can slowly drain the battery.
Their fix is to reduce this current draw by re-programming the ECU and replacing the vent valve with one that operates the same, but at a lower current.
Just changing the vent valve may help a little, but the ECU will still have the old programming.
-OR- take it in, and let them fix it.
Typically, if I leave the car undriven for over 15 hours or so, it will struggle to start. Your suggestions seems like a good set of steps to diagnose if the VCV is actually causing the problem. I will run experiment one of these days, thanks! 1 question though, how do you unplug the VCV electrically? I have the FSM and understand how to remove it physically.
I've contacted a reliable and reputable shop and they confirmed that only those with the consult III (pretty much only nissan/infiniti) would be able to reprogram my ECM. I confirmed with the Infiniti parts department that my ECM does need reprogramming but I'm **** out of luck as I'm past warranty.
I'm not sure if the updated VCV will work positively, negatively, or neutrally with an outdated ECM. If the updated VCV indeed operates at a lower current and the outdated ECM is still controlling the electricity delivery at the same rate, wouldn't it me operating more frequently than desired?
To electrically disconnect the vent control valve:
(1) Locate eval canister (aka charcoal canister) at the rear of the underbody of the car.
(2) Push on the locking tab on the electrical connector, pull on the plug until it is removed from the canister
Be aware, this may give you a check engine light after a while, so don't do this is you are due for emission inspection.
As for your last point:
The new vent control valve has a larger (more turns of wire) coil for the solenoid. This gives will give the same force, but at a lower current.
It is possible that just the new coil alone may not reduce the issue enough and it could still be a problem. If you want a gaurenteed fix, just take it to the dealer for the proper fix. (ECU update and new next control valve)
My action plan would be:
(1) Unplug the vent control valve
(2) See how the car starts after sitting 15+ hours
If it starts up normal, you have identified the issue.
If it starts up slowly, then you have a different issue.
To electrically disconnect the vent control valve:
(1) Locate eval canister (aka charcoal canister) at the rear of the underbody of the car.
(2) Push on the locking tab on the electrical connector, pull on the plug until it is removed from the canister
Be aware, this may give you a check engine light after a while, so don't do this is you are due for emission inspection.
As for your last point:
The new vent control valve has a larger (more turns of wire) coil for the solenoid. This gives will give the same force, but at a lower current.
It is possible that just the new coil alone may not reduce the issue enough and it could still be a problem. If you want a gaurenteed fix, just take it to the dealer for the proper fix. (ECU update and new next control valve)
My action plan would be:
(1) Unplug the vent control valve
(2) See how the car starts after sitting 15+ hours
If it starts up normal, you have identified the issue.
If it starts up slowly, then you have a different issue.
SonicVQ - I found your response thread from 4 years ago...I am troubleshooting an alternator-battery drain issue in another thread, thinking I need to check this selenoid if my new battery drains tonight.
SonicVQ - I found your response thread from 4 years ago...I am troubleshooting an alternator-battery drain issue in another thread, thinking I need to check this selenoid if my new battery drains tonight.
Good plan!
Be careful removing the 10mm bolts that hold on the rear under body cover, to access the vent valve.
They will be rusted and if you apply too much force, they will snap.
Actually, this morning I was checking the wiring diagrams to see if there is a single fuse that could be removed to get the effective same test as disconnecting the vent valve.
As it turned out, there are multiple circuits on that same fuse, so it wouldn't work. Too bad... that would be a quick and easy way to test.
03-15-2016, 02:05 PM
