Overnight Dead Battery- 2020 Serria 1500 Denali

jawsmon · December 27, 2023

Apparent Parasitic Drain on the battery.

The battery goes flat dead overnight. It is so dead the starter solenoid doesn't even click and the radio won't come on. This problem is becoming more and more frequent. This has happened 3 times during the past 2 weeks. There is nothing wrong with the battery. It appears to be a parasitic draw on the electrical system when the truck is turned off. I saw where the 2021's have had this same problem which turned out to be the ECM not completely shutting down. The correction for that particular year has been to get the ECM program updated. Have any of you 2020 owners experienced this problem? If so, what if anything did you do to correct it?

No error code shows up on the scanner.

Ref. https://gmauthority.com/blog/2021/05/gm-releases-fix-for-2021-chevy-silverado-gmc-sierra-battery-drain-issue/

Edited December 27, 2023 by jawsmon
update info

Transient · December 27, 2023

2020 Trail Boss LT still on original battery. No issues so far.

redwngr · December 27, 2023

There is supposed to be some draw on a shutdown vehicle.

Parasitic draws test can be done to determine if the draw is what it is supposed to be.

If it's higher than spec, test continues to determine source of draw.

There is also a 'shipping mode' available that reduces the amount draw when shutdown.

Trotorx2 · December 27, 2023

My battery doesn't go dead but when it sits for a day or two it is slow to start. Took it to the dealer and they changed the battery. Part of the issues went away but slow to start is still there.

jawsmon · December 28, 2023

It has to be something other than the battery since it has load-tested great several times. Under normal conditions, it starts and runs great. The volt meter shows 14 volts and everything works properly. I know, everyone like to point to an easy fix but that's not the case this time.

The problem is duplicating the problem so a tech can witness it for themselves. If you have ever shut off your vehicle and sat inside for 5-10 minutes you will hear a lot of electronic activity as components are shut off and potentially put to sleep. In my opinion, there is something that, on occasion, doesn't quite get the message and continues to consume power. This same problem has been identified in the 2021 GM trucks. The fix is to update the ECM program. I'm wondering if the 2021 problem may have started a little earlier in the 2020.

ember1205 · December 29, 2023

22 hours ago, jawsmon said:

It has to be something other than the battery since it has load-tested great several times. Under normal conditions, it starts and runs great. The volt meter shows 14 volts and everything works properly. I know, everyone like to point to an easy fix but that's not the case this time.

The problem is duplicating the problem so a tech can witness it for themselves. If you have ever shut off your vehicle and sat inside for 5-10 minutes you will hear a lot of electronic activity as components are shut off and potentially put to sleep. In my opinion, there is something that, on occasion, doesn't quite get the message and continues to consume power. This same problem has been identified in the 2021 GM trucks. The fix is to update the ECM program. I'm wondering if the 2021 problem may have started a little earlier in the 2020.

A fully charged battery should show 12.6V, not 14.

Bikerjon · December 31, 2023

On 12/27/2023 at 12:56 PM, jawsmon said:

Apparent Parasitic Drain on the battery.

The battery goes flat dead overnight. It is so dead the starter solenoid doesn't even click and the radio won't come on. This problem is becoming more and more frequent. This has happened 3 times during the past 2 weeks. There is nothing wrong with the battery. It appears to be a parasitic draw on the electrical system when the truck is turned off. I saw where the 2021's have had this same problem which turned out to be the ECM not completely shutting down. The correction for that particular year has been to get the ECM program updated. Have any of you 2020 owners experienced this problem? If so, what if anything did you do to correct it?

No error code shows up on the scanner.

Ref. https://gmauthority.com/blog/2021/05/gm-releases-fix-for-2021-chevy-silverado-gmc-sierra-battery-drain-issue/

There is a test procedure for battery draw. I have used a test light in series between the battery + post and the + battery wire. Some draw is normal but the light will illuminate until you disconnect the source of the draw (usually removing fuses one at a time until the light goes out will indicate which circuit is at fault). This test probably should be conducted by a Certified Technician unless you really know what you are doing. However if this is an intermittent fault the problem may not show itself during testing. Very frustrating but that is how intermittent failures are.

GMCustomerService · January 3, 2024

On 12/27/2023 at 1:56 PM, jawsmon said:

Apparent Parasitic Drain on the battery.

The battery goes flat dead overnight. It is so dead the starter solenoid doesn't even click and the radio won't come on. This problem is becoming more and more frequent. This has happened 3 times during the past 2 weeks. There is nothing wrong with the battery. It appears to be a parasitic draw on the electrical system when the truck is turned off. I saw where the 2021's have had this same problem which turned out to be the ECM not completely shutting down. The correction for that particular year has been to get the ECM program updated. Have any of you 2020 owners experienced this problem? If so, what if anything did you do to correct it?

No error code shows up on the scanner.

Ref. https://gmauthority.com/blog/2021/05/gm-releases-fix-for-2021-chevy-silverado-gmc-sierra-battery-drain-issue/

This is certainly not what we like to hear, jawsmon. Please know, customer satisfaction is extremely important to us. Our team would be more than happy to take a closer look into the concerns with your 2020 GMC Sierra's electrical system. To do so, please send an email to [email protected] with ATTN: jawsmon/GM Trucks in the subject line.

Please include your contact information, VIN, a brief description of your concern, and the name of your preferred dealership. We look forward to hearing from you. To learn more about GM’s Privacy Policy, please visit https://www.gm.com/privacy-statement.html. The information you provide may be monitored and recorded and is subject to the GM Privacy Statement.

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Steve Scire · May 8, 2024

I also have the problem with my 2020 Denali 1500 Duramax. The dealer has had it for two days and AGAIN can't find anything wrong. First battery changeout which is battery #2 in the truck came approx. two years or less after owning the truck. I changed it out myself and 6 or so months later the truck died, and the dealer said I had bought a bad battery. SO, I purchased the battery #3 from dealer and behold months later I was stranded in the driveway again. Battery #4 went into the truck from the dealer because again they can't find anything wrong. This time I was told if it happens again to not jump start the truck so they can test it with the dead battery. WELL, months later again it strands me in the driveway 3 hours from home. So, I had no choice except to jump it. I drove it home and the next day had the dealer test everything and found nothing wrong. Months after that the truck died in my driveway and I made sure the flatbed driver dragged the truck onto the flatbed and took it to the dealer. Unfortunately, the person taking the truck off the flatbed jumped he truck. The dealer tested the battery and gave me the #5 new battery. That was the last week of March 2024. Now two days ago May 6th the truck stranded me again! it had only been approx. 6 weeks. So, it sits at the dealer for 2 days after I made sure to follow the truck driver to the dealership to make sure NOBODY started the truck so they can test it dead. Just got a call that the GM Tech and the dealer tech cannot find the problem and here is a new battery #6. Are there more 2020 trucks having the same issues and are they getting fixed???

GMCustomerService · May 8, 2024

53 minutes ago, Steve Scire said:

I also have the problem with my 2020 Denali 1500 Duramax. The dealer has had it for two days and AGAIN can't find anything wrong. First battery changeout which is battery #2 in the truck came approx. two years or less after owning the truck. I changed it out myself and 6 or so months later the truck died, and the dealer said I had bought a bad battery. SO, I purchased the battery #3 from dealer and behold months later I was stranded in the driveway again. Battery #4 went into the truck from the dealer because again they can't find anything wrong. This time I was told if it happens again to not jump start the truck so they can test it with the dead battery. WELL, months later again it strands me in the driveway 3 hours from home. So, I had no choice except to jump it. I drove it home and the next day had the dealer test everything and found nothing wrong. Months after that the truck died in my driveway and I made sure the flatbed driver dragged the truck onto the flatbed and took it to the dealer. Unfortunately, the person taking the truck off the flatbed jumped he truck. The dealer tested the battery and gave me the #5 new battery. That was the last week of March 2024. Now two days ago May 6th the truck stranded me again! it had only been approx. 6 weeks. So, it sits at the dealer for 2 days after I made sure to follow the truck driver to the dealership to make sure NOBODY started the truck so they can test it dead. Just got a call that the GM Tech and the dealer tech cannot find the problem and here is a new battery #6. Are there more 2020 trucks having the same issues and are they getting fixed???

We are sorry to see you are having battery concerns with your vehicle and would like to investigate this further for you. Please send us an email to [email protected]. Be sure to include your Username and Forum name in the subject line with additional details. We look forward to hearing from you.

Lindsay Vincent · December 23, 2024

I too am having this issue with my 2020 Yukon SLT. I purchased it from a private dealership at the end of March this year. Less than a week of having the car I experienced my first dead battery. It was so dead it couldn't be unlocked with the fob. I was only able to manually pull the key from the fob and open the drivers door to pop the hood and jump the vehicle. This happened again about a week later and once again over the summer. Now that the weather is colder, this problem has returned and more frequently (4-5 times a week). I installed a new battery and tested the alternator (which is good). Two weeks ago, finally too scared to continue jump starting my car for fear of damaging an electrical system I took it into a local mechanic. Of course the first day they had it, the car started with no issues. Per my request, they kept the car for the weekend and found it dead on Monday morning. Unfortunately, after their diagnostics they told me the car "shows an electrical draw. The computer turns on, then randomly puts the car back into sleep/off mode. With the age of the vehicle, it's most likely a computer/software issue that they recommend the dealership should look at as programming and or update may be needed to correct." Hearing this, I immediately scheduled a service appointment at a GMC dealer and showed the service writer the paperwork from my local mechanic. Instead of letting the vehicle sit and wait for the car to "die", they went right to work trying to "diagnose" the issue with no luck. I have requested again that the dealer keep the car and let it sit over the weekend to see if it's dead for them Monday morning. While the car has been at the dealership I decided to do some research on carfax for the service records on this car. Turns out this has been an ongoing issue with the car since 6k miles. It has been to multiple dealerships for electrical issues. The battery was replaced at 17k miles, but the problem has only persisted. It has been to the dealership for the battery replacement and electrical issues 4 times prior to me purchasing it. This is now the 6th time the car has been looked at for this issue. I love my car, but can't afford to fix a major electrical problem that could happen if the dealer is unable to resolve the issue and I have to continue to jump the car, not to mention the inconvenience of having a dead car almost every morning. At what point does GMC step forward and take responsibility for their faulty car as the expense to hunt down and diagnose this issue will most likely be very costly and should have been covered under warranty? I'm at a loss at this point as I'm sure I will get a call from the dealer tomorrow stating they can't figure out the problem. Has anyone been able to find some resolution to this issue?

Marcelo cruz27 · May 12

I have a 2020 GMC sierra 5.3 Denali and I can’t turn the truck off for more than two hours because is draining my battery and I bought a new battery and new alternator and new starter and I still have the same problem I can jump it an the truck runs fine I tried pulling one fuse at a time to what it was and I still can’t figure out this problem I also need help with this.

rcslotcar · May 13

On my 2020 6.2 AT4 the battery posts looked clean with out any corrosion. The battery posts and clamps had developed a light tarnish between them. I cleaned the posts and clamps with a wire brush. This solved the problem for a couple of months until I needed a new battery. I think the bad connection took a toll on the battery.

Mike Duhaime · May 13

On 12/22/2024 at 9:56 PM, Lindsay Vincent said:

I too am having this issue with my 2020 Yukon SLT. I purchased it from a private dealership at the end of March this year. Less than a week of having the car I experienced my first dead battery. It was so dead it couldn't be unlocked with the fob. I was only able to manually pull the key from the fob and open the drivers door to pop the hood and jump the vehicle. This happened again about a week later and once again over the summer. Now that the weather is colder, this problem has returned and more frequently (4-5 times a week). I installed a new battery and tested the alternator (which is good). Two weeks ago, finally too scared to continue jump starting my car for fear of damaging an electrical system I took it into a local mechanic. Of course the first day they had it, the car started with no issues. Per my request, they kept the car for the weekend and found it dead on Monday morning. Unfortunately, after their diagnostics they told me the car "shows an electrical draw. The computer turns on, then randomly puts the car back into sleep/off mode. With the age of the vehicle, it's most likely a computer/software issue that they recommend the dealership should look at as programming and or update may be needed to correct." Hearing this, I immediately scheduled a service appointment at a GMC dealer and showed the service writer the paperwork from my local mechanic. Instead of letting the vehicle sit and wait for the car to "die", they went right to work trying to "diagnose" the issue with no luck. I have requested again that the dealer keep the car and let it sit over the weekend to see if it's dead for them Monday morning. While the car has been at the dealership I decided to do some research on carfax for the service records on this car. Turns out this has been an ongoing issue with the car since 6k miles. It has been to multiple dealerships for electrical issues. The battery was replaced at 17k miles, but the problem has only persisted. It has been to the dealership for the battery replacement and electrical issues 4 times prior to me purchasing it. This is now the 6th time the car has been looked at for this issue. I love my car, but can't afford to fix a major electrical problem that could happen if the dealer is unable to resolve the issue and I have to continue to jump the car, not to mention the inconvenience of having a dead car almost every morning. At what point does GMC step forward and take responsibility for their faulty car as the expense to hunt down and diagnose this issue will most likely be very costly and should have been covered under warranty? I'm at a loss at this point as I'm sure I will get a call from the dealer tomorrow stating they can't figure out the problem. Has anyone been able to find some resolution to this issue?

Mike Duhaime · May 13

Brand:	Model:	Model Year:		VIN:		Engine:	Transmission:
Brand:	Model:	from	to	from	to	Engine:	Transmission:
Chevrolet	Silverado	2021-2024		All	All	All	All
GMC	Sierra 1500 (New Model)	2019		All	All	All	All
GMC	Sierra	2020-2024		All	All	All	All

Involved Region or Country	North America
Additional Options (RPO)	QK2 - Multi-Flex / MultiPro Tailgate
Condition	Some customers may comment that the battery goes dead.
Cause	The cause of this condition could be the GM Accessory Kicker Multi-Flex / MultiPro Tailgate Speaker System.

Correction: On vehicles equipped with GM Accessory Kicker Multi-Flex / MultiPro Tailgate Speaker System, disconnect the X88B 7 way connector at rear bumper trailer receptacle that feeds the Kicker Speaker System and evaluate for a draw. If draw is gone, contact Kicker at 800-256-0808 extension 6007 for additional diagnostics and warranty support as this an Associated Accessory. See latest version of 22-NA-244: GM Accessories - Dealer-Installed, Repaired or Replaced During Warranty Coverage Period.