Dead battery...2020 L5P

Revspan · June 1, 2020

Drove my truck last week, and went to move it today and the battery was completely dead. Good that it was in my garage and not locked.

anyone hear of some kind of parasitic drain issue?

truck has 2k miles on it...absolutely no mods.

thanks

onlymeamy · June 1, 2020

I had the same thing happen to me this morning. I am in a loaner vehicle from the dealer, but the truck has a little over 1000 miles. Dealer is going to look at it today.

MTU Alum · June 1, 2020

The only thing you can do yourself is shutoff the truck, open and close drivers door, and sit in the truck and see if anything does not go asleep. Generally, the green light on onstar is last to go out.

You also could measure the mA draw across the battery after the truck has gone asleep.

#iworkforGM

Oneswtredhead · June 16, 2020

I have a 2020 Chevy Silverado 2500HD diesel. I’ve had it a month. It’s almost to 2000 miles. I drove it Saturday with no issues. Stayed home Sunday. And today, Monday it’s completely dead. I have 2 batteries, husband said both are dead. Nothing was left on, no doors left open, nothing out of the usual. Why would two brand new batteries be dead for no reason?? Dealer is closed, will call them in the morning.

redwngr · June 18, 2020

On 6/16/2020 at 12:07 AM, Oneswtredhead said:

I have a 2020 Chevy Silverado 2500HD diesel. I’ve had it a month. It’s almost to 2000 miles. I drove it Saturday with no issues. Stayed home Sunday. And today, Monday it’s completely dead. I have 2 batteries, husband said both are dead. Nothing was left on, no doors left open, nothing out of the usual. Why would two brand new batteries be dead for no reason?? Dealer is closed, will call them in the morning.

Any add-on accessories? Dash cam? Device plugged into OBD port?

Even if door left open it should have gone into battery protection mode.

Battery Power Protection
This feature shuts off the dome and reading lamps, if they are left on for more than 10 minutes after the
ignition is turned off. The cargo lamp shuts off after 20 minutes. This prevents the battery from running down.

Exterior Lighting Battery Saver
The exterior lamps turn off about 10 minutes after the ignition is turned off, if the parking lamps or
headlamps have been manually left on. This protects against draining the battery.

To restart the 10-minute timer, turn the exterior lamp control to the 0 position and then back to the 'park light' or 'headlight' position.
To keep the lamps on for more than 10 minutes, the ignition must be on or in ACC/ACCESSORY.

It's possible one of the batteries is/was/went bad. When a battery is bad, the good one will try and charge the bad one -- and can result in two dead ones.

Could also be a stuck relay not disconnecting power the way it was commanded.

Let us know what they find.

Oneswtredhead · June 18, 2020

1 hour ago, redwngr said:

Any add-on accessories? Dash cam? Device plugged into OBD port?

Even if door left open it should have gone into battery protection mode.

Battery Power Protection
This feature shuts off the dome and reading lamps, if they are left on for more than 10 minutes after the
ignition is turned off. The cargo lamp shuts off after 20 minutes. This prevents the battery from running down.

Exterior Lighting Battery Saver
The exterior lamps turn off about 10 minutes after the ignition is turned off, if the parking lamps or
headlamps have been manually left on. This protects against draining the battery.

To restart the 10-minute timer, turn the exterior lamp control to the 0 position and then back to the 'park light' or 'headlight' position.
To keep the lamps on for more than 10 minutes, the ignition must be on or in ACC/ACCESSORY.

It's possible one of the batteries is/was/went bad. When a battery is bad, the good one will try and charge the bad one -- and can result in two dead ones.

Could also be a stuck relay not disconnecting power the way it was commanded.

Let us know what they find.

No add-on accessories, nothing left on. Got it into the dealership today. They said both batteries are good. They said the most they could find was because of the radio issue where the radio got stuck on loud volume once & twice the screen was blank on start up. But fixed itself after a restart. The dealer said the radio needed an update & they think it was something associated with that issue that drained the batteries. They can’t find any other issues.

MTU Alum · June 18, 2020

After the vehicle goes asleep, there should be less than 50 mA of draw on the battery(ies). If it is more than 50, some module is not shutting down.

#iworkforGM

MesaRat · July 5, 2020

Have the same problem and upon jump starting it gave me a trailer error. let it run for 20min and was able to restart it. after about 4 restarts it stopped reporting a trailer error but had the CEL on. After a few more restarts all errors/lights were off/normal.

i do have an aftermarket amp/system that is powered directly from the battery (fused). i am also using an intercept harness that delivers low current power source from the vehicle to a digital processor. i have checked multiple times during the day and everything is remaining in a shutdown mode. it has been running with no issues for a month now and is operating fine. however, if truck dies again it again i will disconnect the aftermarket system and return it to stock.

going in weds and i assume GM service can pull up codes even if the CEL has turned off.

Edited July 5, 2020 by MesaRat

dudleyfj40 · July 10, 2020

Hey guys, Just got my 1500 6.2 with 700 miles on it back from the shop for the same dead battery issue. From what the dealership told me, that brake modulator stayed on when It was shut off. I guess there is a Bulletin on this issue. They claimed to reprogram the modulator and all should be fine now.

MTU Alum · July 10, 2020

8 hours ago, dudleyfj40 said:

Hey guys, Just got my 1500 6.2 with 700 miles on it back from the shop for the same dead battery issue. From what the dealership told me, that brake modulator stayed on when It was shut off. I guess there is a Bulletin on this issue. They claimed to reprogram the modulator and all should be fine now.

HDs have a totally different brake system eboost vs hydroboost. It sounds like some other module is staying awake on HDs.

#iworkforGM

Stand By · July 10, 2020

4 hours ago, MTU Alum said:

HDs have a totally different brake system eboost vs hydroboost. It sounds like some other module is staying awake on HDs.

#iworkforGM

Your post just triggered an old memory of an accident back when the charger was undergoing patrol car testing by the Michigan State Police at the Grattan Raceway near Grand Rapids. MSP does thorough patrol car testing of all manufacturers and publishes their review nation wide. They use GM proving grounds, M.I.S. Grattan and their own drive track. The testing troopers are academy drive track instructors and receive NASCAR training.

During this accident, the driver launched the car into a turn and rolled the vehicle right in front of the Chrysler engineers. I later heard the break control module wasn't processing the driver input quick enough for the vehicle to react. Supposedly he went into a 45 mph turn at about 90 and reported the vehicle was not reacting to his braking. MSP suspended the vehicle from the program. Within a few weeks, Chrysler came up with a software update and the vehicle was put back into the program. This was at a time after Chevy had quit producing rear wheel drive cars and Ford was barely increasing any performance of the bland Crown Vic. and SUV's were entering the field.

Muleytime · July 16, 2020

I had this happen once on my 2020 HD AT4. Luckily it was in my garage, and I was able to put a charger on it for a couple of hours. After, it started right up. The CEL stayed on for a couple of days but hasn't been back on since.

I have a feeling that it's something to do with the trailer electronics. I had just pulled my boat the day before and when I disconnected, the truck acted like it was still connected or trying to connect. Just a gut feeling......

Pelicanrick · July 22, 2020

I have a 2020 2500HD 4 x 4 and this is the second time I have had a dead battery. Earlier in the past two weeks I have had black infotainment screen although it comes back on with a restart. Dealership cant find anything on it and claims random draw on the system. First time different dealership changed the battery as a "one time customer courtesy". This time at different dealership they say battery is checking just fine.

Maryland · August 18, 2020

Googling around and came upon this forum while trying to educate myself on possible solutions.

Long story short:

2020 GMC

3500HD Sierra Denali 4WD Crew Cab – Standard Box

Eng: L5P duramax 6.6L Turbo-Diesel

Twice in 2 months.

Won't crank, won't start.

Can't even get out of park. Towed

In dealership twice. They updated some modules due to service bulletins first time. Second time could find no issue and sent it home.

Battery is not the issue (full charge)

I suppose next step is directly contacting GMC? Has anyone had success doing this?

Obviously, scheduled road trips and vacations on hold.

RossEGCA · August 18, 2020

I had the same issue with my 2020 Sierra AT4 HD. I jumped it the first time and it was fine. Second time I charged overnight and it was fine. I took it to the dealer as it threw some check engine codes due to low voltage. they cleared the codes and tested the battery and said it was fine. I said then why does it keep dying? They don't know. So far its been 4 weeks and no other problems. Strange thing is with two batteries there were no warning signs like slow start, etc. Just went from fine to dead overnight.

Edited August 18, 2020 by RossEGCA