2022 Rivian R1T

Rivian R1T P0AA6 HV Isolation Fault — HV Sensor Wire Chafed on Frame Rail

P0AA6 RIV_BMS_0x14 Published 2024-07-29 Updated 2024-07-29
Rivian R1T P0AA6 HV isolation chafed wire frame rail sensor

2022 Rivian R1T presented with P0AA6 HV isolation fault after off-road use. Isolation resistance 18 kΩ on positive bus. HV battery monitoring sensor wire chafed through insulation on a frame rail edge — likely from repeated chassis flex during off-road operation.

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The Problem
2022 Rivian R1T Adventure Package (39,100 miles) towed in after 'Powertrain Fault' and P0AA6 appeared during an off-road trail run. Vehicle had completed moderate-difficulty trails for approximately 4 hours before fault appeared. Would not enter Drive mode.
Diagnostic Procedure
  1. 1. Confirm P0AA6. BMS reports HV positive bus isolation: 18 kΩ (spec: >500 kΩ). Negative bus: >1 MΩ.
  2. 2. Positive bus fault. Disconnect HV positive at main junction to segment circuit. After disconnecting the battery monitoring system (BMS sense harness) at the front junction point: isolation jumps to >1.2 MΩ. Fault in BMS sense harness or its routing.
  3. 3. Physical inspection of BMS sense harness routing from battery pack along left frame rail. Harness secured with factory P-clips at 300mm intervals.
  4. 4. At the third P-clip from the front (approx. 600mm behind front axle centerline): harness has shifted off the clip and is in contact with a raw frame rail stamping edge. 80mm section of outer jacket worn through, exposing inner conductor.
  5. 5. Off-road chassis flex allows the clip to disengage, and repeated movement of the harness against the rail edge over 4 hours of trail use abraded through the insulation.
  6. 6. Repair harness: re-insulate exposed section with dual-wall heat shrink, re-route with additional clearance, secure with new P-clip plus cable tie safety.
  7. 7. HV isolation check: positive bus >1.5 MΩ. Clear P0AA6. Vehicle enters Drive normally.
  8. 8. Test drive including moderate off-road simulation. No fault return.
Resolution & Root Cause
BMS sense harness repaired and re-routed with additional clearance from frame rail. Isolation restored, P0AA6 resolved.
💡 Key Lesson
Rivian R1T off-road chassis flex can disengage harness P-clips that appear secure during static inspection. P0AA6 appearing during or after trail use — inspect the BMS sense harness along the frame rails for chafe points. Frame rail stamping edges are particularly aggressive on harness insulation once a clip disengages.
About This Case

This case was solved remotely by an HVDesk specialist with 15+ years of hands-on experience across major EV platforms including Tesla, Hyundai/Kia, Volkswagen ID series, BMW i-series, and Ford EVs. The procedure was provided as structured remote support to an independent auto repair shop.