Hi everyone. I used to post quite frequently on this forum many years ago, heck I even remember when the .org was founded! I since left for a while to help run the nissanmurano.org forum (when I picked one up in 2003) but still have the Maxima, and its been fantastic, except for a recent electrical problem that perhaps I can get some advice on.

Problem: If car is not driven for four or five days, the battery is drained and car will not start.

What I did: Battery and alternator checked out fine, so I searched for a parasitic drain. Hooked up my ammeter to the battery, and measured a 300mA parasitic drain with everything turned off (lights, doors closed, key not in ignition, etc..). Started pulling fuses and finally got a drop to ~30mA when I pulled the BCM fuse. So, something is keeping the BCM awake and thats slowly draining the battery. I checked all the door/trunk/hood switches, no interior lights (or the trunk light) were staying on, and no door ajar indicator so I don't think its any of the switches. At this point, I don't know what else to check.

Any advice you can give would be appreciated!

 

To add more to the story, I've noticed the battery saver function, which shuts off the interior lights/headlights, hasn't been working for a while now either.

 

Have you tried to run BCM self tests?

 

You might have a break in the wire and its probably grounding to somewhere in the car.

 

What is the procedure for this?

 

Possibly, but I'd like to rule out the easy stuff before tackling the hard stuff. So with the BCM, I'm thinking of whatever is tied to it which receives power with the ignition off - for example, an interior dome light or one of the door ajar sensors (the black plunger thing) on the frame. I've checked the usual suspects - interior lights (trunk, dome, glovebox), door sensors (the door ajar light does not stay lit on my dash and I can arm the stock alarm without it flashing two or three times). What else could I be missing before I am forced to remove the entire center stack to get at the BCM?

 

Are you waiting long enough before checking for a parasitic drain? The bcm doesn't go into 'sleep mode' until after a certain amount of time has passed, you might just have a dead battery and no drain.

But checking the bcm codes is to lengthy to describe/re-write, it starts on page 195 of the EL section of the FSM, which can be found at http://www.vq35de.com/ESM/Nissan/Maxima/

 

You are right, aprox. after 30s BCM should enter the "sleep" mode, but author told that battery saving function, which turns off the interior lights doesn't work. It could indicate that the BCM operates in a fail-safe mode.

I wonder why this and front-oxygene sensor checking procedure is not in the stickies...

 

Thanks for the link to the FSM - I have a paper copy somewhere (huge thick book) but can't seem to find it now. Interesting point about the BCM operating in fail-safe mode - if this is the case, wouldn't it just cut power to the defective LCU in order to prevent the bad LCU from causing a power drain? I'll have to try the self diagnostic sometime.

 

also, have you tried reseting the ecu.

 

Yes, disconnected the battery overnight to make sure the battery itself could hold a charge (it could). I'm sure that was enough time for the ECU to power down.

 

I realize that im bringing up an old thread but im new here so this is the only way i can post something. my brother has a 97 maxima that he hasnt driven in a while (moved on to a new car with plans of fixing the maxima and selling it). heres the details of the situation: the battery drains within a few days of not driving it. ive hooked up an ammeter in series with the battery and another one thru the BCM circuit. with the doors open the current thru the battery is around 175mA and the BCM is around 65mA, doors closes the current thru the battery is around 55mA with the BCM pulling just under 50mA. ive let it sit for 5 minutes just to make sure i gave it enough time to "sleep" but nothin changed. when i disconnect the meter to the BCM to cut the power thru it, the current thru the battery drops to 25mA. ive checked all the door switches, trunk and hood switches and they all work. I did notice tho that my glove box light doesnt come on. the switch works fine and the light is not burnt out, so im guessin the problem is something related to that. anyone have any idea or possibly a BCM diagram? ive been searching and cant find any.

 

There is a thread called Parasitic Drian Help where Matty resolved his drain issue. At that time I checked my Maxima which works normally, you may want to compare to my measurements.

I checked my 98 SE which works normally and does not have this problem. I opened my hood and checked current with everything else off and closed. The draw was approximately 0.1 Amps = to 100 milliamps. This is the same as Matt's result. If I depress the switch that senses if the hood is closed after about 30-60 seconds the current draw goes down to about 0.01 Amps or 10 milliamps. This must be the sleep mode kicking in. That is quite a a difference. I can understand if another switch from the alarm system is malfunctioning, of missing, the car would never go into sleep mode.