Comprehensive battery pack testing procedure for the 2024 Rivian EDV 500 to assess high-voltage battery health, capacity, cell balance, and overall system integrity using diagnostic equipment.

Warnings

Tools required

Parts

• High-voltage connector service cover (if damaged) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Ensure battery state of charge is between 20-80% for accurate testing (charge or discharge as needed)
3. Allow battery pack to stabilize at ambient temperature for minimum 2 hours if vehicle was recently driven or charged
4. Verify Rivian diagnostic software is updated to latest version
5. Don high-voltage insulated gloves and verify integrity (no tears or damage)
6. Review vehicle history for any prior battery-related fault codes or customer complaints
7. Ensure fire extinguisher rated for electrical fires is accessible
8. Place high-voltage warning signs around vehicle work area

Procedure

1. 1

   Connect diagnostic scan tool
   Connect Rivian diagnostic scan tool to vehicle's OBD-II port located below driver side dashboard. Power on tool and establish communication with Battery Management System (BMS), High Voltage Battery Controller, and Electric Drive Unit modules. Verify all systems communicate successfully before proceeding.
2. 2

   Retrieve baseline fault codes and data
   Scan all vehicle modules and record any existing fault codes, paying special attention to battery-related codes (P0A00-P0AFF range and manufacturer-specific codes). Document current battery state of charge, battery voltage, individual cell group voltages, battery temperature readings from all sensors, and charge/discharge cycle count. Save data log for comparison.
3. 3

   Perform initial visual inspection
   Remove lower underbody panels to access battery pack enclosure using 10mm socket. Inspect battery enclosure for physical damage, deformation, corrosion, or coolant leaks. Check all high-voltage cable connections for secure fit, orange cable condition, and connector integrity. Inspect cooling system hoses connected to battery pack for leaks or damage. Document any findings with photos.
4. 4

   Check battery coolant level and condition
   With engine bay access, visually inspect EV battery coolant reservoir level (do not open). Coolant should be between MIN and MAX marks. Check coolant color through reservoir (should be clear to light pink). If coolant is dark, contaminated, or level is low, note for separate service. Use thermal camera if available to scan battery pack for temperature inconsistencies indicating coolant flow issues.
5. 5

   Perform static voltage measurements
   Using diagnostic tool, command vehicle into service mode. Navigate to high-voltage battery monitoring screen and record total pack voltage. Record individual module voltages (EDV 500 has multiple modules). Calculate voltage deviation between highest and lowest module - deviation should be less than 0.5V. Document all readings including individual cell group voltages if accessible through diagnostic system.
6. 6

   Execute BMS cell balance test
   Through diagnostic software, initiate cell balancing routine if battery shows voltage imbalance. Monitor balancing progress for 20-30 minutes. BMS will discharge higher voltage cells through balancing resistors. Observe that voltage spread between cell groups decreases during balancing. After balancing, re-check module voltages and verify improvement in balance (target less than 0.2V spread).
7. 7

   Perform isolation resistance test
   Using diagnostic tool, command high-voltage isolation test. This tests insulation resistance between high-voltage system and vehicle chassis ground. Monitor test results - isolation resistance should exceed 500 ohms per volt (minimum 200kΩ for 400V system). Values below specification indicate potential insulation breakdown requiring immediate attention. Record measured isolation resistance values.
8. 8

   Execute capacity test preparation
   Verify state of charge is between 90-95% for capacity test (charge vehicle if needed using Level 2 charger until target SOC reached). Allow battery to rest for 30 minutes after charging. Ensure ambient temperature is recorded. Connect current clamp meter to one of the high-voltage cables if available for external current monitoring during discharge test.
9. 9

   Perform controlled discharge capacity test
   Using diagnostic tool, initiate controlled discharge test routine. BMS will discharge battery at specified rate while monitoring capacity. Test typically runs 30-45 minutes depending on starting SOC. Monitor battery temperature throughout test - temperatures should remain under 113°F (45°C) and all modules should heat relatively evenly. If thermal runaway protection activates or temperatures exceed limits, abort test immediately. Record total energy discharged and compare to rated capacity specifications.
10. 10

    Analyze discharge curve and internal resistance
    Review discharge curve data from diagnostic tool. Curve should show smooth, linear voltage decline under load. Sudden voltage drops or irregularities indicate cell degradation. Calculate internal resistance from voltage drop under load versus no-load voltage. Compare internal resistance to factory specifications (typically increases with age/use). Elevated internal resistance indicates battery degradation.
11. 11

    Test high-voltage interlock loop
    Verify high-voltage interlock loop (HVIL) circuit integrity through diagnostic tool. This safety circuit runs through all high-voltage connectors and service disconnect. Manually disconnect and reconnect service disconnect (typically located in rear cargo area) while monitoring HVIL status on scan tool. System should immediately detect disconnection and report open HVIL circuit. Reconnect and verify HVIL circuit shows closed/intact.
12. 12

    Perform thermal analysis
    If thermal imaging camera is available, scan entire battery pack underbody while battery is at operating temperature (after capacity test). Look for hot spots indicating individual cell failures or cooling system blockages. Temperature variation across pack should be minimal (within 10°F). Compare thermal image to previous service records if available. Document thermal patterns with saved images.
13. 13

    Generate battery health report
    Using diagnostic software, generate comprehensive battery health report. This includes state of health (SOH) percentage, remaining capacity versus new capacity, charge/discharge cycle history, any degradation trends, and overall battery grade. Rivian system will provide A-F grade based on all test parameters. Document SOH percentage and overall grade. SOH below 70% may indicate battery warranty consideration.
14. 14

    Verify all systems and clear diagnostic mode
    Exit service mode through diagnostic tool. Clear any temporary fault codes generated during testing (do not clear pre-existing codes). Command vehicle to normal operating mode. Verify high-voltage system re-initializes properly and ready indicator illuminates on dash. Confirm all battery cooling pumps operate normally. Test drive vehicle briefly to confirm normal operation and regenerative braking functionality.

Reassembly

1. Reinstall all underbody panels removed for inspection, ensuring proper clip and fastener engagement
2. Verify all high-voltage connector covers and service covers are properly installed
3. Remove high-voltage warning signs from work area
4. Clean work area of any tools or equipment

Verification

• Confirm battery state of health (SOH) is documented and meets acceptable parameters (typically >80% for warranty coverage)
• Verify all module voltages are balanced within 0.2V of each other
• Confirm isolation resistance test passed with values exceeding 500Ω/V minimum specification
• Verify no new fault codes are present in Battery Management System
• Test regenerative braking operation during test drive - should engage smoothly without warnings
• Confirm battery capacity test results match or exceed degradation expectations for vehicle age and mileage
• Verify high-voltage interlock loop functions correctly and responds to service disconnect
• Document all test results, thermal images, and battery health report in vehicle service records for future comparison

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