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2025 R1S 12V Battery Drain - 'Service Required' Message & No Start

0

David L. · rep 0 · May 25, 5:03 AM · 1 replies · solved · Question

Vehicle: 2025 Rivian R1S Max Pack

My 2025 Rivian R1S Max Pack has been giving me intermittent trouble starting. Sometimes it's completely dead, and I get a generic 'Service Required' message on the screen, along with other seemingly random electrical glitches. After a jump start (which is a bit confusing on an EV!), it usually runs fine for a day or two, then the problem recurs.

I suspect the 12V battery might be the culprit, but I thought EVs didn't have 'starting' batteries in the traditional sense. Is this a common issue with Rivians, and what are the signs of a failing 12V battery in an electric vehicle? Any specific things I should look for or check?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 5:03 AM

0

ClearTheCode admin answer:

  1. 12V Battery in EVs: You're right to suspect the 12V battery! While the high-voltage battery powers the drivetrain, the 12V auxiliary battery is crucial for starting up the vehicle's computers, infotainment, lights, power windows, and safety systems. If it's dead, the car won't 'wake up' or allow the high-voltage system to engage.

  2. Signs of a Failing 12V Battery:

    • 'Service Required' Message: Often a generic warning for electrical system faults.
    • No Start/No Power: Vehicle completely unresponsive, even if the main battery is charged.
    • Random Electrical Glitches: Flickering lights, unresponsive infotainment, erratic warnings, or features not working correctly.
    • Slow or Failed Boot-up: The vehicle takes longer to 'start' or fails to do so entirely.
    • DTCs: You might find codes like B1xxx (Body Electrical), P0Axx (High Voltage System - often triggered by low 12V), or Uxxxx (Communication) if the low voltage disrupts module communication.

  3. Common Causes for 12V Battery Issues:

    • Parasitic Draw: Something is continuously drawing power when the vehicle is off, draining the battery. This can be a faulty module, accessory, or even a software bug.
    • Aging Battery: Like any lead-acid or lithium-ion 12V battery, it has a finite lifespan and can degrade over time, especially in extreme temperatures.
    • Charging System Issue: The DC-DC converter (which charges the 12V battery from the high-voltage battery) could be faulty, preventing the 12V from recharging properly.
    • Loose Connections: Corroded or loose battery terminals can prevent proper charging or power delivery.

  4. Troubleshooting Steps (Limited DIY):

    • Check Battery Voltage: If you have a multimeter, check the voltage across the 12V battery terminals (usually located under the frunk or in a service panel). A healthy battery should read ~12.6V when off and ~13.5-14.5V when the vehicle is 'on' (indicating the DC-DC converter is working).
    • Inspect Terminals: Ensure the battery terminals are clean and tight. Look for any corrosion.
    • Record Symptoms: Note down exactly what happens, what messages appear, and when it occurs to help technicians diagnose.

  5. When to See a Shop:

    • Persistent Problem: Since this is recurring, it's not just a one-off glitch. A dead 12V battery can strand you.
    • Contact Rivian Service: While you can check basic voltage, diagnosing parasitic draws or issues with the DC-DC converter or the battery itself requires specialized tools and expertise. Rivian service can accurately test the 12V battery's health, check for parasitic drains, and inspect the charging system to resolve the root cause.
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