Electrical issue - Battery drain

[wkreps]

Same issue as original poster on a 2009 Aveo. Base model 4 door sedan. About the only add-ons are Cruise control, Air-conditioning, Automatic transmission and CD player. I have had the battery drained twice in the last two weeks. Jumped it today and drove it for 15 minutes. The battery charged to 12.55 volts when I parked it. Here's a list of measurements I took throughout the day as it sat in my driveway.

8:25a . . . 12.55v
10:55a . . . 12.07v
12:35p . . . 11.96v
4:15p . . . 11.74v
5:45p . . . 11.71v (unhooked ned terminal)
8:15p . . . 11.74v (hooked up neg terminal again)
Update
10:30p . . . 6.15v
Popped back on the resistor and measured it, .500v draw. Pulled the SJB fuse and it went to 0.0. Plugged it back in and it settled back to the .365v
10:40p . . . 4.60v (yes in 10 minutes it dropped 1.5v)
This is getting out of hand. What could cause it to make that leap just sitting there. Car is in a garage and it's 33F outside so Temp shouldn't be an issue. Is my battery toast? It's only 10 months old and it replaced the original factory battery. Not too keen on replacing the battery until the real problem is fixed.

After watching this youtube video - http://www.youtube.com/watch?v=B__DqK90IIc -

I'm sorry but I don't really know anything electrical but here's what I did after installing the 1 ohm - 10 watt resistor between the neg post on the battery and the neg post clamp. I set my multimeter to 20 volts and took all measurements from either side of the resistor inline like mentioned above.

The base reading was .365v which I'm guessing is the draw on the battery. I proceeded to take out the fuses in the engine compartment one by one and observing the results. The only engine compartment fuse that changed the reading was the 50A SJB Batt fuse and the reading went to 0.0v.

From previous posts this led me to the fuse box by the driver door.

When I opened the driver door the reading went from the base of .365v to .395. (my guess is the door light in the cluster came on, note: the dome light was set to off position). It stayed at .395v as I removed each fuse one by one checking for changes. The only changes in the readings are noted below.

10A Cluster/RoomLamp removal lowered the reading from .395v to .380v. When I plugged it back in, it spiked to .700v but dropped slowly back down over a minute or two to the .395 reading.

15A Door Lock removal lowered the reading from .395v to .380v. Note: I have manual door locks (scratching head).

10A OBD removal lowered the reading from .395v to .045v. I then closed the driver door and waited a minute and the reading went even lower to .012v.

So it looks like I've isolated it to the OBD fuse (like others here) but how do I go about troubleshooting each one of these modules. Also where do you find out about what fuses control what parts of the car like GTOKID mentions below? How do I find out what the battery draw should be on this 2009 Aveo? I'll edit this post and add reading times since I've rehooked back up the neg battery terminal at 8:15p.

QUOTE GTOKID wrote:
"The OBD feeds the Data link connector, theft deterrant module, pass presence sensor, restraint sensing module and vehicle comm module. Guess I need to disconnect each one of these to isolate further......"

Note: The owners manual states the OBD fuse usage as DLC, Immobilizer. These weren't listed in GTOKID's post. Any ideas what they are?

[floorrunner]

just got a car in the shop today for this issue. 09 pontiac g3. anyway removed obd2 fuse and problem went away. found that there is a module under the driver seat, with a white and a yellow connector on it. i unplugged the white connector and the draw is now gone. hopes this helps you guys out. i will find out what the part is and a little more about it soon. thanks Chad a tech from A plus Automotive in Dinuba, CA

looks like its for the on-star system part# 96964229

[wkreps]

I took mine into the Chev dealer today. They just called and said they may get to it tom but they have seen where OnStar could cause this kind of drain. Then I come on here and see your post, sounds promising although the price of the part you list runs 500 - 800 dollars.

[MetroMPG]

just got a car in the shop today for this issue. 09 pontiac g3. anyway removed obd2 fuse and problem went away. found that there is a module under the driver seat, with a white and a yellow connector on it. i unplugged the white connector and the draw is now gone. hopes this helps you guys out. i will find out what the part is and a little more about it soon. thanks Chad a tech from A plus Automotive in Dinuba, CA

looks like its for the on-star system part# 96964229

Chad - THANKS for that info.

[wkreps]

Just got a call from the Chev dealer and it was the OnStar module causing the battery drain. Two options available:
1.) The mechanic already did some rewiring to bypass something and the drain is gone but the OnStar will not work in the car. Bill= $108
2.) Replace the OnStar module (price forthcoming).

I will definitely try and get the rewiring specs from the dealer (if they will share) and share them here so that others can "fix" this issue.

[PoisonIvy]

You would hope that GM would cover the cost on that. But we know they won't. It's their stupid device that is obviously rendering some of their cars unusable. It's scary to think in another decade how many issues these electronics are going to give people trouble. I'm fortunate I can afford new or nearly new cars. Or alternatively afford the repair bills, but not everyone can.

[Daox]

Thanks for the update wkreps.

[avguy]

....The mechanic already did some rewiring to bypass something and the drain is gone but the OnStar will not work in the car. Bill= $108
...
I will definitely try and get the rewiring specs from the dealer (if they will share) and share them here so that others can "fix" this issue.

...found that there is a module under the driver seat, with a white and a yellow connector on it. i unplugged the white connector and the draw is now gone. .....

Sounds like the "rewiring" is so simple that even a stealership can do it.

[wkreps]

found that there is a module under the driver seat, with a white and a yellow connector on it. i unplugged the white connector and the draw is now gone.

So it was $108.90 out the door for the "FIX". I had the dealer mechanic tell me and explain exactly what he did (and I thanked him for it).

Explanation on my receipt
Found Onstar module staying "awake" and causing drain on battery. OBD fuse powers up OnStar module and Air Bag module Diagnose and remove power feed circuits from OnStar module connector X1. Terminals 15 and 16.

I made a crude drawing of what the mechanic drew out for me (see below). The power runs from the SJB fuse in the engine compartment to the OBD fuse in the driver compartment. The power splits there and one side goes to the SDM (Air Bag Module). The other leg splits again and goes to the VICM (Vehicle Interface Control Module/OnStar Module). The mechanic didn't know why the OnStar needed two power leads but he removed them both and taped them off individually. Yes floorrunner, there is a yellow and white plug under the front of the driver seat. The two power leads for the OnStar are in the white plug, terminals 15 and 16. They are both red wires with a white line on them. Note, this does fix the power drain but disables the OnStar as there is no power going to it. The dealer wanted $780 for a new OnStar module. I opted to disable it and run without it. I never subscribed anyways.

I hope this helps everyone out there.

[Thymeclock]

So it was $108.90 out the door for the "FIX". I had the dealer mechanic tell me and explain exactly what he did (and I thanked him for it).

The dealer wanted $780 for a new OnStar module. I opted to disable it and run without it. I never subscribed anyways.

I hope this helps everyone out there.

I find it remarkable that we haven't heard from the girls at GM (the Chevy reps) who used to chime in on this list constantly. Their recent silence is a welcome relief. The ongoing helpful support we give each other as Aveo owners is priceless and deserving of recognition.

Thanks for posting this. You may have saved all us Aveo owners $780 in the future, dealing with the electronic crap that GM embedded and wired into our Aveos.