My Rivian R1S says "Service 12V battery system." What do I do?

Short answer: On an R1S, a 12-volt warning, system fault or turtle mode usually means a weak 12-volt battery or a poor connection, and the car can go dead soon after. On one 2025 R1S, a faulty zone control module triggered a false warning. Book Rivian service right away. If you're far away, a flatbed tow (Rivian or AAA) is safer than limping in. Ask them to check the 12-volt terminals as well as the battery.

Symptom: 'Service 12V battery system immediately', a system fault, AWD warnings, speed limited to turtle mode, or a car that's dead the next morning.

What to check first

1. Check the low-voltage reading in service mode if you know how; owners treat over 13 volts as healthy.
2. Book Rivian service as soon as the warning appears.
3. Ask them to check the 12-volt terminals and the battery, and for any module faults.
4. Use AAA or Rivian roadside for a flatbed if it's in turtle mode far from service. Ask Rivian about tow charges first.
5. Run your VIN at nhtsa.gov/recalls.

Likely causes

1. Weak 12-volt battery. Almost every modern car, including EVs and hybrids, has a small 12-volt battery that powers the computers, locks and screens. When it's weak, the car can show a pile of unrelated warnings or refuse to go into gear, even with a full main battery. Rivian owners report their 12-volt batteries wearing out within a few years.
2. Loose 12-volt terminal. One owner's 12-volt terminal wasn't tightened fully after a replacement, causing intermittent warnings.
3. Faulty zone control module. On one 2025 Gen 2 R1S, the 12-volt warning was false: the service center replaced a faulty south zone control module (one of the car's body computers) under warranty.

What it usually costs

Owners had repairs under warranty. One owner said Rivian would charge $850 for a tow if it wasn't a warranty issue.

Is it safe to keep driving?

Not for long. Owners went into limited power and woke up to dead cars. Plan to get it to service, towed if needed.

DIY or shop?

Reading the voltage in service mode is DIY. Battery and module work is best left to Rivian. An EV's high-voltage system can stay live with the car off. Leave the orange cables, the big battery and the drive unit to a trained EV technician.

Recalls, bulletins and complaints in plain words

• Related recalls: NHTSA lists 22 recalls for the R1S in these years. One, 25V537000, covers some 2025 R1S and R1T: an improperly grounded connection inside the high-voltage distribution box may cause a loss of drive power. Check your VIN at nhtsa.gov/recalls. If your car is part of a recall, the dealer fixes it for free.
• Plain words: The complaint count below shows how often owners reported problems that mention these words to NHTSA. A count is not proof of a defect.
• NHTSA complaints: 42 keyword-matched complaints for Rivian R1S 2022–2025 (of 152 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-31; keywords: 12 v, battery, drive system, won t, warning, loss of power, dead). This counts complaints that mention these words. It is not a defect finding.

What owners report

• In 2025 Gen 2 R1S Possible False 12V Warning on Reddit r/Rivian, a 2025 Gen 2 R1S showed a 12-volt battery warning and went into turtle mode (limited power). Service found a faulty south zone control module and replaced it under warranty, and the 12-volt tested fine. Other owners checked their 12-volt voltage in service mode and saw over 13 volts.
• In 12V, system fault, AWD on Reddit r/Rivian, a Gen 1 R1S with 45,000 miles went into turtle mode with 12V, system fault and AWD warnings right after a touchless car wash, and was dead the next morning, so AAA towed it. The owner said Rivian would charge $850 for its own tow if the repair wasn't covered by warranty. Others said a failing 12-volt can set off random faults.
• In Continued 12v battery issue — how concerned should I be? on Reddit r/Rivian, an R1S got 'service 12V battery system immediately' after its first week. Rivian replaced the 12-volt, but the warning returned days later, though a hard reset let them keep driving. A commenter said a 12-volt terminal left loose after a replacement caused the same intermittent warnings.

Quick tip

Don't ignore the first 12-volt warning. The cars in these threads gave a day or two of notice, then left owners stranded.

Vehicle focus: Rivian R1S, 2022-2025 (Gen 1 and Gen 2).

Safety / mechanic note

Turtle mode and sudden shutdowns are safety risks. Verify with a mechanic.