Inverter R&R

This procedure covers the removal and replacement of the power inverter assembly on a 2023 Chevrolet Bolt EUV with 65 kWh single motor drivetrain, including high-voltage system de-energization and drive unit component access.

Warnings

Tools required

Parts

• Power inverter assembly × 1 — Use OEM specification
• High-voltage connector seals/boots × 2 — Included with inverter or order separately
• Coolant (if contaminated) × 1 — ACDelco DEX-COOL Orange
• Thermal interface pad/compound × 1 — Use OEM specification

Fluids

• ACDelco DEX-COOL (Orange) — 1.5 qt

Preparation

1. Park vehicle on level surface and apply parking brake
2. Ensure vehicle has been off for minimum 15 minutes to allow high-voltage system to stabilize
3. Verify you have high-voltage safety certification and proper PPE (insulated gloves, safety glasses, insulated tools)
4. Place high-voltage service warning placard on steering wheel
5. Disconnect 12V auxiliary battery negative terminal and wait 2 minutes
6. Raise vehicle on lift or secure on jack stands with all four wheels off ground
7. Remove engine undercovers and splash shields to access drive unit
8. Place drain pan under inverter coolant connections
9. Document all high-voltage connector positions and orientations with photos

Procedure

1. 1

   De-energize high-voltage system
   Remove rear seat lower cushion to access high-voltage battery service disconnect. Using insulated tools, unlock and remove the high-voltage battery service disconnect plug. Install lockout/tagout device to prevent reconnection. Wait minimum 5 minutes for high-voltage capacitors to discharge.
   ⚠️Do not proceed until 5 minutes have elapsed after removing service disconnect. Capacitors retain lethal voltage.
2. 2

   Verify zero voltage
   Put on high-voltage insulated gloves. Using a high-voltage capable multimeter, verify 0V DC between high-voltage positive and negative bus bars at the inverter connections. Test multimeter on known voltage source before and after to confirm meter functionality. Document voltage readings.
   ⚠️If any voltage is detected, do not proceed. Reconnect service disconnect, wait 1 minute, then repeat de-energization procedure.
3. 3

   Drain inverter coolant
   Locate the coolant hoses connected to the inverter assembly on the drive unit. Place drain pan underneath. Carefully release the hose clamps and disconnect the coolant supply and return lines from the inverter. Allow coolant to drain completely. Cap or plug open coolant lines to prevent contamination.
   ⚠Coolant may be warm. Wear appropriate gloves and eye protection.
4. 4

   Disconnect low-voltage electrical connectors
   Locate all low-voltage connectors on the inverter assembly including temperature sensors, resolver connectors, and control module connectors. Press release tabs and carefully disconnect each connector. Move harnesses aside and secure to prevent damage during inverter removal.
   Torque spec

   Sensor Bolts11 Nm (8 lb-ft)

   Connector Bolts7 Nm (5 lb-ft)
5. 5

   Remove high-voltage cable cover
   Remove the protective orange cover over the high-voltage connections on the inverter. Remove the cover screws securing the high-voltage terminal shield. Carefully set cover aside, noting orientation for reinstallation.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
6. 6

   Disconnect high-voltage cables
   While wearing high-voltage insulated gloves, remove the high-voltage connector bolts securing the positive and negative DC bus cables from the battery, and the three-phase AC cables to the motor. Carefully separate connectors, avoiding any bending of bus bars or contact pins. Inspect connector seals and boots for damage. Move cables aside and secure away from work area.
   ⚠️Even though system is de-energized, treat all orange cables as live. Never allow high-voltage positive and negative to contact simultaneously or short to vehicle ground.
   Torque spec

   Connector Bolts7 Nm (5 lb-ft)
7. 7

   Remove inverter mounting brackets
   Locate the support brackets that secure the inverter to the drive unit housing. Remove bracket bolts securing any support or grounding brackets. Keep brackets organized for reinstallation in correct positions.
   Torque spec

   Bracket Bolts20 Nm (15 lb-ft)
8. 8

   Remove inverter mounting bolts
   Locate the main inverter mounting bolts that secure the inverter assembly to the drive unit transaxle housing. There are typically 4-6 mounting bolts around the perimeter of the inverter. Remove all mounting bolts and keep them organized. Support the weight of the inverter before removing the final bolt.
   ⚠Inverter weighs approximately 25 lbs. Ensure adequate support before removing final mounting bolt to prevent dropping.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
9. 9

   Remove inverter assembly
   Carefully pull the inverter assembly away from the drive unit housing. The inverter interfaces with the motor/transaxle through a thermal interface and mounting dowels. Work the inverter free with gentle rocking motion if needed. Once clear, lower inverter and remove from vehicle. Inspect mounting surface on drive unit and inverter mating surface for damage or debris.
   ℹ️Do not pry against electrical components or circuit boards. Use only designated lifting points on inverter housing.
10. 10

    Prepare new inverter
    Remove new inverter from packaging and inspect for shipping damage. Verify part number matches application. Clean mounting surface on drive unit housing with clean shop towel. Apply new thermal interface pad or compound to inverter mating surface per manufacturer specifications. Ensure all mounting dowel holes are clean and clear.
    ℹ️Proper thermal interface material is critical for inverter cooling and longevity. Use only specified OEM thermal compound or pads.
11. 11

    Install new inverter assembly
    Carefully position new inverter assembly onto the drive unit, aligning mounting dowels with holes in inverter housing. Ensure inverter seats fully against drive unit housing with no gaps. Start all mounting bolts by hand to ensure proper thread engagement before tightening.
    Torque spec

    Mounting Bolts27 Nm (20 lb-ft)
12. 12

    Reinstall mounting brackets and grounds
    Reinstall all support brackets and grounding straps in their original positions. Ensure all grounding points make clean metal-to-metal contact. Tighten all bracket bolts to specification.
    Torque spec

    Bracket Bolts20 Nm (15 lb-ft)
13. 13

    Reconnect high-voltage cables
    Inspect all high-voltage cable terminals and connector seals. Replace any damaged seals or boots. Apply thin layer of dielectric grease to connector mating surfaces. Carefully align and connect high-voltage cables (DC positive, DC negative, and three-phase AC) to inverter terminals. Ensure proper seating before installing bolts. Tighten high-voltage connector bolts to specification in a crisscross pattern.
    ⚠️Verify correct cable routing and polarity. Reversed polarity will cause immediate component failure when energized.
    Torque spec

    Connector Bolts7 Nm (5 lb-ft)
14. 14

    Install high-voltage cable cover
    Reinstall the protective orange shield over high-voltage terminals. Ensure all cables and connectors are properly seated within cover. Install and tighten cover screws to specification. Verify orange cover is fully secured with no gaps.
    Torque spec

    Cover Screws11 Nm (8 lb-ft)
15. 15

    Reconnect low-voltage connectors and coolant
    Reconnect all low-voltage electrical connectors to inverter including sensors, resolver, and control module connectors. Verify each connector locks with audible click. Reconnect coolant supply and return hoses to inverter, securing with hose clamps. Tighten sensor mounting bolts and connector bolts to specification where applicable.
    Torque spec

    Sensor Bolts11 Nm (8 lb-ft)

    Connector Bolts7 Nm (5 lb-ft)
16. 16

    Refill and bleed cooling system
    Add ACDelco DEX-COOL coolant to cooling system reservoir to proper level. Start 12V system (do not energize high-voltage yet) and run coolant pump through bleed procedure per service manual to remove air from inverter cooling circuit. Check for coolant leaks at all connections. Top off coolant as needed.
    ℹ️Air in inverter cooling circuit will cause overheating and component damage. Ensure proper bleeding procedure is followed.
17. 17

    Reinstall undercovers and lower vehicle
    Reinstall all engine undercovers and splash shields. Verify all fasteners are secure. Lower vehicle to ground. Perform final visual inspection of all connections and components.
18. 18

    Re-energize high-voltage system
    Reconnect 12V auxiliary battery negative terminal. Remove lockout/tagout device from high-voltage service disconnect. Reinstall high-voltage battery service disconnect plug, ensuring it locks securely. Replace rear seat cushion. Remove high-voltage service warning placard from steering wheel.
    ⚠️Once service disconnect is reinstalled, high-voltage system is live. Do not touch any orange cables or components.

Reassembly

1. Torque all fasteners to specification using values provided in procedure
2. Ensure all high-voltage connectors have proper seals and orange protective covers installed
3. Verify coolant system is properly filled and bled with no leaks
4. Confirm all low-voltage electrical connectors are fully seated and locked
5. Double-check that no tools or parts were left in vehicle

Verification

• Connect scan tool and verify no high-voltage system DTCs are present
• Perform high-voltage isolation test per manufacturer procedure to verify no current leakage to chassis ground (should read >500 megohms)
• Start vehicle in READY mode and verify inverter cooling pump operates
• Monitor inverter temperature with scan tool - should remain stable during idle
• Perform brief test drive and verify normal acceleration with no warning lights
• Check for coolant leaks after test drive, particularly at inverter connections
• Verify all vehicle systems operate normally including regenerative braking
• Clear any stored DTCs that may have been set during service disconnect
• Document repair with inverter part number, date, and mileage for service records

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