Why won't my VW ID.4 turn on even though the big battery is charged?

Short answer: An ID.4 can be completely dead even with a charged main battery, because the car's computers, locks and start-up all run on a small 12-volt battery. If that battery goes flat or weak, the car won't wake up. Owners get in with the hidden key, jump the 12-volt system at the marked posts, and the car then recharges it. A weak 12-volt battery, older software, or a charging fault (one is a recall) can cause it.

Symptom: The car won't unlock with the fob or app, won't power on, won't release the charging cable, or shows a message like '12V power supply is currently limited.'

What to check first

1. Check your VIN for recalls, especially 25V125 (2024 ID.4: the part that charges the 12-volt battery may fail) and 22V956 (2023 rear-drive ID.4: a 12-volt charging cable may rub and short).
2. Get in with the mechanical key hidden in the fob. Owners say the door cover needs removing to reach the lock.
3. Jump the 12-volt system using the positive battery post and the marked ground post, not the battery's negative post. VW's tip sheet explains the order.
4. Ask the dealer to test the 12-volt battery with a proper load test and check for software updates.
5. If you replace the 12-volt battery, have it registered (coded) to the car so it charges it correctly.

Likely causes

1. Weak or failing 12-volt battery. Owners report 12-volt batteries weakening after about two years.
2. Older software. Owners say flat 12-volt batteries were more common on older software and less common after updates.
3. 12-volt charging fault (recall 25V125 on 2024 models). Free fix if your VIN is included.
4. Chafed 12-volt charging cable (recall 22V956 on 2023 rear-drive models). Free fix if your VIN is included.

What it usually costs

Owners in these threads didn't post repair prices. A portable jump pack is inexpensive and worth keeping in the car. Recall repairs are free.

Is it safe to keep driving?

If it starts after a jump, it's usually fine to drive while the car recharges the 12-volt battery, but get it checked soon. VW's recall 25V125 warns that a failed 12-volt charging part can cause a loss of drive power, so if you see a 12-volt warning while driving, pull over safely and get it to a dealer. Verify with a mechanic.

DIY or shop?

DIY for getting in and jump-starting with a jump pack using the marked posts. Dealer for recalls, software updates and battery registration.

Recalls, bulletins and complaints in plain words

• Recall 25V125 (2024 ID.4): the part that charges the 12-volt battery may fail and stop charging it, which can cause a loss of drive power. If your car is part of this recall, the dealer fixes it for free.
• Recall 22V956 (2023 rear-drive ID.4): the 12-volt battery charging cable may rub against the steering column shaft and short circuit. If your car is part of this recall, the dealer fixes it for free.
• Other recalls: NHTSA also lists ID.4 recalls for the high-voltage battery, motor coolant seal, and gear display. Check your VIN at nhtsa.gov.
• NHTSA complaints: 43 keyword-matched complaints for Volkswagen ID.4 2021–2024 (of 989 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-22; keywords: 12V, 12-volt, low voltage, battery died or dead, won't start, no power, locked out). This counts complaints that mention these words. It is not a defect finding.

What owners report

• In ID4 12v problems -- can't get in the car! on VW ID Talk, a new 2024 ID.4 owner couldn't unlock the car or release the charger in the morning. Members said it sounded like a dead 12-volt battery, explained the hidden key and the hatch trick, and said the car recharges the 12-volt quickly once on. One member said his original 12-volt was failing at two years.
• In Jumpstart? on VW ID Talk, owners said jumping the ID.4 from a jump pack or another car is fine using the red and black posts made for it. One said dead 12-volt batteries happened a lot on older software and less on newer versions. They said not to use the ID.4 to jump other cars.
• In 12 volt error on VW ID Talk, a 15,500-mile owner got '12V power supply is currently limited' and read a low battery health number with a scan app. Members said cold weather makes a weak 12-volt worse, that dealers often don't test it properly, and that a replacement battery must be coded to the car.

Quick tip

On any EV, keep a small jump pack in the car. The big battery can be full and you're still stuck if the little one is dead.

Vehicle focus: 2021–2024 Volkswagen ID.4 (all versions).

Safety / mechanic note

A failing 12-volt supply can cause a loss of drive power. Verify with a mechanic.