Why is my Polestar 2 completely dead and won't unlock or start?

Short answer: When a Polestar 2 goes totally dead (no screen, won't unlock, won't go into drive), the usual cause is the small 12-volt battery, not the big drive battery. The car needs the 12V battery to wake up. You can jump it at the front jump points shown in the owner's manual. If it keeps happening, the 12V battery probably needs replacing, and a few owners also needed a control module replaced.

Symptom: Black screen, no response to the key or phone, the car stuck 'on' after a jump, or a 'Critical 12V charging fault' message.

What to check first

1. Try a jump at the front jump points described in the Polestar manual, following the connection order it gives.
2. If you see '12 V battery fuse failure, service required', the manual says a fuse has blown and needs service.
3. If it dies again soon, have Polestar test the 12V battery and look for whatever is draining it.
4. Check your VIN for recall 21V110 (a separate high-voltage software issue on 2021–2022 cars).

Likely causes

1. Discharged or worn-out 12V battery. Owners replaced the 12V battery and the car worked normally again. An r/Polestar thread lists the spec owners used: an H6 AGM, 70 Ah, 760 CCA battery.
2. Charging or software fault draining the 12V. One Polestar Forum owner had the 12V die while plugged in, in two different cars; service called the first case a software glitch.
3. Failed vehicle control unit (VCU). One r/Polestar owner's car needed both a new VCU and a new 12V battery.

What it usually costs

I couldn't find a reliable published price. Owners replaced the battery themselves or at a local shop; warranty may cover it on newer cars, so ask Polestar first.

Is it safe to keep driving?

If it won't wake up, it won't drive, so it's mostly an inconvenience. If it dies repeatedly or shows charging faults, get it checked before a long trip. Verify with a mechanic.

DIY or shop?

DIY for a jump or battery swap if you're comfortable and use the correct battery type. Polestar service if it keeps dying or shows charging faults.

Recalls, bulletins and complaints in plain words

• No recall covers the 12V battery itself.
• Recall 21V110 (2021–2022 Polestar 2): a separate issue where the battery energy control module (BECM, the computer that manages the big battery) can reset and shut off the high-voltage system. The fix is a software update. If your car is part of this recall, it's done for free.
• NHTSA complaints: 3 keyword-matched complaints for Polestar 2 2021–2024 (of 593 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-17; keywords: 12v, 12 v, 12-volt, 12 volt, auxiliary battery, low voltage battery).

What owners report

• On the Polestar Forum, an owner posted Polestar 2 12V dying: the 12V died while plugged in, in both his car and a loaner, dropping so low it had to be replaced.
• In Dead 12v and can't charge it, an owner got a 'Critical 12v charging fault'. Replies shared the battery spec, and another owner said theirs turned out to be the VCU, replaced along with the 12V battery.
• A 2024 Polestar 2 owner had the car stuck 'on' after a jump. A local shop swapped the 12V battery and it worked normally.
• Another owner couldn't charge a dead 12V with a NOCO charger.

My take

My advice as a former lot tech: EVs sitting on a lot kill 12V batteries all the time. If you're buying a used Polestar 2, ask when the 12V was last replaced, and keep a small jump pack in the car.

Vehicle focus: 2021–2024 Polestar 2.

Safety / mechanic note

Repeated charging faults should be checked before a long trip. Verify with a mechanic.