Dead Battery

slimjim2525 · March 3

I just got back from a 2 week snowmobile trip in Quebec. I left my truck at my house in Vermont. Got back, and the battery is totally dead. Would not jump off of jumper cables. Had to call AAA, and they double jumped it with a jump box, and jumper cables. Drove it home 3.5 hours to my house in CT. Shut it off, and sure enough, it wont start. Put a voltmeter on it and is reading 3.3 volts. So I bought a new battery. Now I have a warning to service parking brake and a wrench symbol on the dash. WTF GM?? Off to the dealer I go, and I'm out of warranty as the truck has 40k miles on it.

Transient · March 3

Do you have an OBD2 scan tool? Might be able to clear those codes that are throwing the dash lights. If they come back on you'll know there's a definite problem.

slimjim2525 · March 3

Just saw a video on youtube. To clear this, just start the truck, press the brake, and hold the parking brake button for 10 seconds. It cleared. No trip to the dealer. But still, batteries dying cuz the truck sat for a couple weeks. This is the second time it happened actually. Went on a cruise for a week, came home and same thing, but that time I was able to jump it off my car.

AJMBLAZER · March 3

Have the battery load tested. Makes me wonder if you have a dead cell in it and the battery is showing enough volts across the good cells when charged but as soon as any load is on it battery drains down and fails

Also, with everything on modern vehicles having sensors and/or being electronic when the working voltage gets low all kinds of weird things happen and goofy errors happen.

repairman54 · March 4

16 hours ago, AJMBLAZER said:

Have the battery load tested. Makes me wonder if you have a dead cell in it and the battery is showing enough volts across the good cells when charged but as soon as any load is on it battery drains down and fails

Also, with everything on modern vehicles having sensors and/or being electronic when the working voltage gets low all kinds of weird things happen and goofy errors happen.

Spot on. I just went through this on my '20 Traverse. Load test showed battery borderline weak. Tossed all kinds of crazy codes on a cold start up yet cranked up strong. One would expect more than a few years out of a big AGM battery but not today.

AJMBLAZER · March 4

Eh, manufacturing defects/COVID production issues/the high demand on the electrical systems of modern vehicles/GM probably didn't put in the highest grade batteries/etc. He's also in a cold climate with a diesel. Lots of demands on modern batteries and charging systems.

redwngr · March 5

Any accessory devices (radar detector, dashcams, etc.) connected that might increase the parasitic draw above the factory level?

If not, there is a procedure to determine whatever it is that is causing the abnormal draw.

GETGONE · March 6

There was a TSB on something that was causing parasitic draw from the factory because it wasn't going to the proper shut down state and was sticking in standby mode. It's also helpful to randomly put a battery charger on the truck to top it off. If you're driving short distances and the vehicle sits a lot, it will drain the battery and never get fully charged.

Ben_Drinking_Coffee · March 11

What GETGONE said. I had this issue on an F150 a while back. It was a control module that never shut off properly. We spend months hunting a parasitic drain only to find the transmission said awake all the time and drained the battery. No faults thrown.

Good luck.