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2023 R1S 12V Battery Drain & 'Service HV System' Warning

0

Mike T. · rep 0 · May 25, 5:08 AM · 1 replies · solved · Question

Vehicle: 2023 Rivian R1S Adventure

Hello Rivian community,

I own a 2023 Rivian R1S Adventure, and I've been experiencing a really frustrating problem lately. A couple of times now, after letting the vehicle sit for just 2-3 days, the 12V battery has completely drained, leaving the car unresponsive. I've had to jump-start it twice.

After the last jump, I immediately got a 'Service HV System' warning message on the main display. The vehicle drives fine after the jump, but the warning persists, and I'm worried about the underlying cause. Is this a known issue with the 12V system or something more serious related to the high-voltage battery management?

I've checked for any accessories left on, but everything seems normal. It feels like something is constantly drawing power even when the vehicle is off. Any insights or similar experiences?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 5:08 AM

0

ClearTheCode admin answer:

Experiencing a drained 12V battery, especially coupled with a 'Service HV System' warning, is a critical issue that requires prompt attention. While the 12V battery powers the vehicle's auxiliary systems (lights, infotainment, door locks), its health is intricately linked to the overall high-voltage (HV) system in an EV.

Possible Causes:

  1. Parasitic Drain: An electrical component or module in the vehicle remains active when it should be off, continuously drawing power from the 12V battery. This is a common cause of unexpected battery drain.
  2. Failing 12V Battery: Even in newer vehicles, a defective 12V battery can lose its charge capacity prematurely. The HV system charges the 12V battery, but if the 12V battery itself is faulty, it won't hold a charge.
  3. HV System Fault: The 'Service HV System' warning indicates a potential issue with the high-voltage battery, its management system (BMS), or related components. A fault here could indirectly affect the 12V charging system or cause other modules to malfunction and draw excessive power.
  4. DC-DC Converter Issue: The DC-DC converter is responsible for stepping down the high voltage from the main battery to charge the 12V battery. A fault in this component could lead to the 12V battery not being properly recharged.

Common OBD Codes (may vary by Rivian-specific codes):

  • P0A8D: 12V Battery State of Charge Low.
  • P0AA6: Hybrid Battery Voltage System Isolation Fault (can indicate an issue within the HV system).
  • P0D01: DC/DC Converter Performance (if the converter is failing).

Troubleshooting Steps (Limited):

  1. Check for Active Accessories: Double-check that no interior lights, charging cables, or aftermarket accessories are drawing power when the vehicle is off.
  2. Monitor 12V Voltage (if possible): If you have a multimeter, you can monitor the 12V battery voltage after charging and then after the vehicle sits for a few hours to see how quickly it drops.

When to See a Shop:

  • Immediately. A 'Service HV System' warning is serious and indicates a potential safety or operational risk. Continuing to drive with this warning could lead to further damage or unexpected shutdowns.
  • If the 12V battery continues to drain, even after being fully charged.
  • If you experience any other unusual electrical behavior.

This type of issue requires specialized diagnostic equipment to pinpoint the exact cause, as it could involve complex interactions between the 12V and HV systems. Schedule a service appointment with Rivian as soon as possible.

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