Comprehensive diagnostic testing of the high-voltage battery pack system to verify state of health, capacity, cell balance, and overall performance using Rivian diagnostic tools.

Warnings

Tools required

Parts

• High-voltage service disconnect plug safety cover × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface in well-ventilated area away from flammable materials
2. Ensure vehicle has been off for at least 30 minutes to allow battery temperature stabilization
3. Verify battery state of charge is between 20-80% for accurate testing
4. Put on all required personal protective equipment including high-voltage insulated gloves
5. Chock all four wheels securely
6. Place high-voltage safety mat at driver's side work area
7. Disable 12V power by disconnecting negative terminal of 12V auxiliary battery located in front trunk
8. Wait 2 minutes for vehicle systems to power down completely

Procedure

1. 1

   Access high-voltage service disconnect
   Raise vehicle on lift to access height. Locate high-voltage service disconnect (HVSD) plug underneath vehicle on driver's side near center of battery pack. Remove underbody panel fasteners covering HVSD access port using appropriate tools. The HVSD is a bright orange handle with safety interlock.
2. 2

   Disconnect high-voltage system
   Verify you are wearing Class 0 or higher HV gloves. Rotate HVSD safety cover counterclockwise to unlock. Pull orange HVSD plug straight out from receptacle with firm steady pressure. Inspect plug and receptacle for any signs of arcing, melting, or contamination. Install safety cover on HVSD plug. Place removed plug in secure location away from work area. Wait minimum 5 minutes for HV capacitor discharge.
   ⚠️Do not touch any orange high-voltage cables or connectors during this 5-minute waiting period.
3. 3

   Verify electrical isolation
   Using CAT III rated digital multimeter, verify no voltage present between HV positive and negative bus bars at the disconnect location. Reading should be 0V DC. Also verify isolation between HV positive bus and vehicle chassis ground (should read >500 megohms). Document all readings. If any voltage detected, wait additional 5 minutes and retest.
4. 4

   Connect diagnostic equipment
   Connect Rivian DiagnosticLink interface to vehicle OBD-II port located under driver's side dashboard. Temporarily reconnect 12V auxiliary battery negative terminal to power diagnostic system only. Launch Rivian DiagnosticLink software on laptop. Select '2025 EDV 500 Dual Motor AWD' vehicle profile. Navigate to 'Battery Management System' module.
5. 5

   Retrieve battery system data
   In DiagnosticLink software, select 'Battery System Status' to retrieve current battery parameters. Document: total pack voltage (should be 400-800V depending on state of charge), total pack capacity remaining (%), individual module voltages (all should be within 100mV of each other), pack temperature readings from all sensors (should be 60-80°F for accurate testing), pack cycle count, and any stored diagnostic trouble codes.
6. 6

   Perform cell voltage analysis
   Navigate to 'Cell Voltage Monitor' screen in diagnostic software. Review all individual cell voltages. Battery pack contains multiple modules with cells in series/parallel configuration. All cell voltages should be within 30mV of average for healthy pack. Flag any cells outside this range. Document minimum, maximum, and average cell voltages. Calculate delta (max-min voltage). Delta above 50mV indicates cell imbalance requiring attention.
7. 7

   Check battery thermal profile
   Review battery thermal management system data. Check coolant temperature sensors throughout pack (typically 8-12 sensors). All readings should be within 10°F of each other. If available, use thermal imaging camera on underside of battery pack to visually inspect for hot spots indicating failing cells or thermal management issues. Document any temperature anomalies.
8. 8

   Perform state of health test
   In DiagnosticLink, select 'Battery State of Health Test'. This performs controlled charge/discharge cycle analysis using vehicle's onboard systems. Test takes approximately 45-60 minutes. Software will calculate: actual usable capacity vs. design capacity (should be >85% for healthy battery), internal resistance measurements, and overall battery health percentage. Monitor test progress and do not interrupt.
9. 9

   Execute cell balancing check
   Navigate to 'Cell Balancing Status' screen. Verify Battery Management System (BMS) is actively balancing cells if voltage delta exceeds threshold. Review balancing current for each module (typically 100-200mA per cell). Check total balancing time accumulated. Excessive balancing activity may indicate failing cells. If cell imbalance >50mV detected earlier, initiate manual cell balancing procedure through diagnostic software 'Service Functions' menu.
10. 10

    Test battery management system communication
    Run BMS communication test to verify proper operation of all battery module controllers. Each module should respond to diagnostic queries within 100ms. Test includes: module firmware version verification, CAN bus communication integrity test, sensor functionality check for voltage and temperature sensors. Document any communication errors or non-responsive modules.
11. 11

    Perform insulation resistance test
    Using DiagnosticLink 'HV Insulation Test' function, command BMS to perform automated insulation resistance measurement between HV system and vehicle chassis. Acceptable reading is >500 megohms (typically >1000 megohms for new battery). Values below 100 megohms indicate serious insulation breakdown and battery pack must not be returned to service. Values 100-500 megohms require investigation for moisture intrusion or failing insulation.
12. 12

    Review and analyze test results
    Generate comprehensive battery test report from DiagnosticLink software. Review all parameters against Rivian factory specifications. Key pass/fail criteria: State of Health >85%, cell voltage delta <50mV, insulation resistance >500 megohms, no active battery DTCs, all temperature sensors functional and reading within range, all module controllers communicating properly. Document any failures or borderline results requiring follow-up.
13. 13

    Reconnect high-voltage system
    If battery test results are acceptable and no safety concerns exist, prepare to reconnect HV system. Verify HVSD plug and receptacle are clean and dry. Remove safety cover from HVSD plug. Align plug with receptacle and push firmly until fully seated with audible click. Rotate safety cover clockwise to lock position. Verify orange safety indicator shows system connected status.
14. 14

    Perform system reactivation
    Disconnect 12V auxiliary battery again. Wait 30 seconds. Reconnect 12V negative terminal securely. In DiagnosticLink software, clear any test-related diagnostic codes if appropriate (do not clear codes related to actual faults). Navigate to 'Service Functions' and select 'Exit Service Mode' to restore normal vehicle operation. Power on vehicle and verify Ready indicator illuminates normally with no HV system warning lights.
15. 15

    Final verification and documentation
    Reinstall underbody access panel and secure all fasteners. Lower vehicle from lift. Perform brief test drive monitoring for any unusual battery behavior, warning lights, or performance issues. Verify regenerative braking functions normally. Save complete battery test report from DiagnosticLink. Document test date, mileage, test results summary, and any recommendations in vehicle service records. Provide customer with battery health report showing state of health percentage and estimated remaining capacity.

Reassembly

1. Ensure high-voltage service disconnect plug is fully seated and locked with safety cover engaged
2. Verify all underbody panels are reinstalled and properly fastened
3. Confirm 12V auxiliary battery connections are clean and tight
4. Remove all tools and equipment from under vehicle before lowering

Verification

• Vehicle powers on normally with no high-voltage system warning lights or fault messages
• Battery state of health test shows >85% capacity retention for acceptable condition
• Cell voltage delta is <50mV across all battery cells
• Insulation resistance test reads >500 megohms minimum
• All battery temperature sensors reading normally and within expected range
• Test drive confirms normal electric drive performance and regenerative braking function
• Rivian diagnostic system shows no active battery-related diagnostic trouble codes

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