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2025 Tucson HEV 12V Battery Needs to be Reset

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#101 ·
Guys, I just responded on another thread to the very same issue. It is simple.
1) Remove the Bluelink App from your phone memory after using it. No need to delete the app
2) Delete the digital key if you have configured.
I also had the same issue two weeks into buying this SUV. With suggestions from fellow owners I followed the above steps and for weeks now I am NOT seeing this issue. Unfortunately we are losing the benefits of the digital key but hoping for Hyundai to fix it. The thing is they both keeps pinging your car causing the battery to drain. Hope that helps!
 
#102 ·
I paid my dealer to unplug the phone module (mine is behind the radio in center cluster). Had them disconnect the Sirus module as well.

My two problems solved.
 
#103 ·
shriramemail said:
Guys, I just responded on another thread to the very same issue. It is simple.
1) Remove the Bluelink App from your phone memory after using it. No need to delete the app
2) Delete the digital key if you have configured.
I also had the same issue two weeks into buying this SUV. With suggestions from fellow owners I followed the above steps and for weeks now I am NOT seeing this issue. Unfortunately we are losing the benefits of the digital key but hoping for Hyundai to fix it. The thing is they both keeps pinging your car causing the battery to drain. Hope that helps!
Click to expand...
I am alright with not using my digital key but I want to have Bluelink set up. However, I am scared that I will come across this 12V issue with it set up. Have you had the issue since you made the adjustments that you posted about?
 
#105 ·
Hyundai has issued instruction to pull out the fuse for Bluelink system. They did this to my car( Tucson Hybrid 2025) over a month ago and since then all is OK.
 
#106 ·
ShadowHakudoshi said:
I am alright with not using my digital key but I want to have Bluelink set up. However, I am scared that I will come across this 12V issue with it set up. Have you had the issue since you made the adjustments that you posted about?
Click to expand...
I have not had this issue since then. You can use the Bluelink app when required after which remove from the phone memory. Even tonight I used this app to remotely start the climate. But I really want to use the digital key once it’s solved by Hyundai as I don’t want to carry the key fob .
 
#108 ·
I have a 1.75 year old 2023 Tucson Limited Hybrid with 11K miles. I experienced the 12V battery disconnect for the first time this week after I had parked the vehicle in my garage with the doors locked for 2.5 weeks. When I used the 12V Battery Reset to start the car, I noticed that the hybrid battery gauge showed 50% charge, and it backed out of the garage in EV mode using just the battery. So the battery was not discharged, and the system should not have disconnected the 12V battery tap. So far, it has worked normally in the week since. Has anyone else noted the state of their battery charge after resetting the 12V connection and starting the vehicle? I suspect there is an issue with the disconnect logic, not a battery drain issue. BTW, there is no 12V battery in this vehicle. It is a 12V tap off the hybrid lithium battery. Anyone who thinks they're getting a 12V battery replacement is sorely mistaken.
 
#109 ·
efriedman301 said:
I have a 1.75 year old 2023 Tucson Limited Hybrid with 11K miles. I experienced the 12V battery disconnect for the first time this week after I had parked the vehicle in my garage with the doors locked for 2.5 weeks. When I used the 12V Battery Reset to start the car, I noticed that the hybrid battery gauge showed 50% charge, and it backed out of the garage in EV mode using just the battery. So the battery was not discharged, and the system should not have disconnected the 12V battery tap. So far, it has worked normally in the week since. Has anyone else noted the state of their battery charge after resetting the 12V connection and starting the vehicle? I suspect there is an issue with the disconnect logic, not a battery drain issue. BTW, there is no 12V battery in this vehicle. It is a 12V tap off the hybrid lithium battery. Anyone who thinks they're getting a 12V battery replacement is sorely mistaken.
Click to expand...
The battery gauge is showing the state-of-charge (SOC) of the traction battery not the 12V battery. Hyundai doesn't give us a 12V SOC indication unfortunately.

The 12V battery is not a tap of the HV traction battery. It is a fully separate battery that charges and discharges completely independent of the traction battery. There is no electrical (except ground) connection or physical connection between the 12V battery and HV traction battery. See this post for more discussion (esp post 9):

 
#110 ·
According to the 2023 Tucson HEV Owners Manual, page 8-4: "This vehicle does not have a regular 12V battery that needs periodic replacement. It is lithium ion polymer type integrated into the HEV high voltage battery." IMHO, this clearly states that there is no separate 12V battery in the HEV vehicle, it is an integrated part of the HEV high voltage battery, which you call the "traction battery". I don't know from where the rumor of a separate battery originates, but the Owners Manual for the HEV vehicle is quite explicit. The SOC indication reflects the charge of the HEV high voltage battery, of which the 12V output is an integrated part.
 
#111 ·
efriedman301 said:
... I don't know from where the rumor of a separate battery originates...
Click to expand...
The "rumor" originates from the drawings, schematics, and replacement instructions at hyundaitechinfo.com and kiatechinfo.com. Study the post 9 drawings in the other thread. You'll see the 12V battery. Can't miss it.
 
#112 ·
efriedman301 said:
According to the 2023 Tucson HEV Owners Manual, page 8-4: "This vehicle does not have a regular 12V battery that needs periodic replacement. It is lithium ion polymer type integrated into the HEV high voltage battery." IMHO, this clearly states that there is no separate 12V battery in the HEV vehicle, it is an integrated part of the HEV high voltage battery, which you call the "traction battery". I don't know from where the rumor of a separate battery originates, but the Owners Manual for the HEV vehicle is quite explicit. The SOC indication reflects the charge of the HEV high voltage battery, of which the 12V output is an integrated part.
Click to expand...
You are wrong, period. It does not say there is no 12V battery, it says it does not have a regular 12V battery, meaning what most are used to. There is a 12V battery in the HEV. It is housed and connected to the Traction battery but it is a separate battery that can be replaced if needed. Just not like we are used to.

If you want to actually learn about it ...
www.hyundaimotorgroup.com

Do Hybrid Vehicles Get Discharged? -The Truths About Hybrid Cars

Hybrid vehicles have continued to evolve to achieve higher efficiency. If so, do the hybrid cars these days get discharged? Let's take a closer look at the misunderstandings and truths about the latest hybrid cars and how to respond when the power is cut off.
www.hyundaimotorgroup.com www.hyundaimotorgroup.com
 
#113 ·
efriedman301 said:
I have a 1.75 year old 2023 Tucson Limited Hybrid with 11K miles. I experienced the 12V battery disconnect for the first time this week after I had parked the vehicle in my garage with the doors locked for 2.5 weeks.
Click to expand...
I've never had to use the 12V jump button even when I was on vacation for 25 days. My car is now 3.1945 years old.
 
#114 ·
efriedman301 said:
I have a 1.75 year old 2023 Tucson Limited Hybrid with 11K miles. I experienced the 12V battery disconnect for the first time this week after I had parked the vehicle in my garage with the doors locked for 2.5 weeks. When I used the 12V Battery Reset to start the car, I noticed that the hybrid battery gauge showed 50% charge, and it backed out of the garage in EV mode using just the battery. So the battery was not discharged, and the system should not have disconnected the 12V battery tap. So far, it has worked normally in the week since. Has anyone else noted the state of their battery charge after resetting the 12V connection and starting the vehicle? I suspect there is an issue with the disconnect logic, not a battery drain issue. BTW, there is no 12V battery in this vehicle. It is a 12V tap off the hybrid lithium battery. Anyone who thinks they're getting a 12V battery replacement is sorely mistaken.
Click to expand...
I question if the battery is capable of holding a charge for even 1 week. My 2021 Tuscon Hybrid Limited has been at the dealer for 2 months, waiting for a replacement Lithium battery and BMS, after the dealer finally could not start the car. Yesterday they finally admitted that the battery case was actually warped from the heat of the battery, so I would avoid locking the vehicle up in an enclosed space, just in case of fire.
 
#115 ·
Locked out of my plugged-in but dead brand new 2025 Hyundai Tucson N-line after not driving for awhile. Thanks to everyone for posting, I obviously have a drain too. Can't get into dealership service department for a week! Very frustrated with this new car being less reliable in terms of the 12v battery than the junker I replaced. Also remote start from fob doesn't work, it won't let me set a digital key, the AEB light comes on randomly and the roof makes a flapping noise when a back window is open. Very disappointing.
 
#117 · (Edited)
Reporting in on the same issue for a 2025 Tucson AWD SEL ICE (non-hybrid) here in the US.

I have narrowed this down to an issue with leaving the car unlocked, and then returning to the car after 5-10 minutes of it being left in that unlocked state.

It is easy to replicate the issue:

  • After turning off the car, leave the doors unlocked
  • Return within 5-10 minutes (as soon as the Bluelink app gives you notification that your doors are unlocked)
  • Open and close any door - including hood or trunk hatch
  • You will see your push-button ignition and drivers' side USB port are lit up, and will remain on untli your 12V battery is dead (usually 1-2 days at most)

The only way to clear this condition is to do an ignition cycle (accessory, run, off) and then quickly lock your car with the fob or door handle touchless control within 5 minutes or so of the vehicle being off.

I asked dbest to post that Hyundai Canada 24-22 TSB for us in the states which he said is instructing dealers in Canada to remove fuse #17 (wireless DCU/data connectivity unit) until a permanent fix is made available. as there may be a "logic error in the CCU (central communication unit) and may be triggered by wireless communication." from his original post.

This issue persists no matter if you have multiple user profiles, automatic A/C fan turned on, key fobs near/away, or the digital key enabled. It appears completely unrelated.
 
#118 ·
My Tucson 2025 Hybrid is only 2 months old! Always plugged in under 15⁰C. Battery dead after 7 days not being driven. Had to boost. Had to use restart (though door had to be shut and I had to stay freezing in vehicle with fob) to manually started after 36 hours not driven when it was in -30⁰C. Just dropped off at dealer for battery drain check etc. The service dealer was a rude old crank who tried to tell me I had to pay to put a battery extender on myself. She said all new cars are like this because the manufacturer can't know every ones different driving habits! What a load of crap! We'll see if this dealership in Saskatchewan will admit any issues when I pick up the vehicle this afternoon. This is complete crap. Happy to join the class action suit.
 
#120 ·
Update on my issue from my post #117 on this thread:

Ended up being an OTA/over-the-air software update that was "stuck" and caused the wireless DCU (cellular) module to stay on, thus drawing power. My radio actually showed it had an update available in the settings menu, but would give an error message if you tried to apply that update.

Radio software was manually updated by the dealer via their hardwired diagnostic tool (not OTA), but the issue could happen again if future OTA/over-the-air updates get hung up.

After this update to the radio software, the USB and ignition button lights now properly turn off automatically after 5 minutes following the trigger of a door opening/closing.

So far so good!
 
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