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"High Voltage System Fault" light on 2025 R1S

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Mike T. · rep 0 · May 25, 5:05 AM · 1 replies · solved · Question

Vehicle: 2025 Rivian R1S Adventure

I just got a "High Voltage System Fault" warning light pop up on my 2025 Rivian R1S Adventure model. It came on while I was driving normally, and I didn't notice any immediate performance degradation, but it's definitely unsettling. The orange wrench icon is also illuminated.

I tried restarting the vehicle, but the warning persists. I haven't had any charging issues or power loss before this.

What exactly does this warning mean for a Rivian? Is it safe to drive to the service center, or should I call for a tow?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 5:05 AM

0

ClearTheCode admin answer:

A "High Voltage System Fault" warning, especially when accompanied by an orange wrench icon, indicates a serious issue within your Rivian R1S's high-voltage electrical architecture. While you might not feel an immediate performance change, this warning should not be ignored.

Common Causes:

  1. HV Contactor Issues: The high-voltage contactors are essentially large relays that connect and disconnect the main battery pack from the rest of the vehicle's high-voltage system. A fault here (stuck open/closed, excessive resistance) can trigger this warning.
  2. Battery Management System (BMS) Sensor Fault: The BMS constantly monitors voltage, current, and temperature across the battery cells. A faulty sensor or a communication error within the BMS can incorrectly report an issue or fail to detect a real one.
  3. High Voltage Insulation Resistance Fault: The vehicle's system continuously checks for unintended paths for high voltage current (i.e., shorts to ground). If the insulation around HV cables or components degrades, it can trigger an isolation fault.
  4. DC-DC Converter Issue: This component converts the high voltage from the main battery to 12V for the auxiliary systems. A fault here can sometimes cascade into a broader HV system warning.

Diagnostics:

Common OBD-II codes associated with such a warning include:

  • P0AA6: Hybrid Battery Voltage System Isolation Fault
  • P0A7A: High Voltage Battery Contactor Stuck Open
  • P0A0E: High Voltage System Interlock Circuit High

When to See a Shop:

  1. Safety First - Do Not Drive: If you receive a "High Voltage System Fault" warning, it is generally not safe to drive the vehicle. There is a potential risk of electrical hazard, further system damage, or unexpected power loss. The vehicle's systems are designed to detect faults that could compromise safety.
  2. Call for a Tow: Your safest course of action is to contact Rivian Service immediately and arrange for your R1S to be towed to the nearest service center. Do not attempt to charge the vehicle either, as this could exacerbate the problem.
  3. Professional Diagnosis Required: Rivian technicians have specialized training and equipment to safely diagnose and repair high-voltage systems. Attempting to troubleshoot this yourself is strongly discouraged due to the inherent dangers of high-voltage electricity.
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