Perform diagnostic testing of the high-voltage charging system on the 2023 Chevrolet Bolt EUV to verify proper operation of the onboard charger, charge port, and battery charging acceptance.

Warnings

Tools required

Preparation

1. Ensure vehicle is parked on level ground in a well-ventilated area
2. Verify battery state of charge is between 20-80% for optimal test conditions
3. Ensure vehicle is in Park with parking brake applied
4. Power off vehicle completely and remove key fob from interior
5. Visually inspect charge port door and charge port for damage, debris, or corrosion
6. Inspect high-voltage battery enclosure underbody for any signs of damage or leakage
7. Connect GM MDI diagnostic scanner to vehicle OBD-II port and establish communication

Procedure

1. 1

   Perform pre-test visual inspection
   Open the charge port door located on driver side front fender. Inspect charge port contacts for corrosion, burning, or damage. Check the charge port locking mechanism operates freely. Inspect charge port wiring harness connector for proper seating and damage to weather seals. Verify orange high-voltage cable routing near charge port area is secure with no abrasion or damage to insulation.
2. 2

   Retrieve diagnostic trouble codes
   Using GDS2 software on the MDI scanner, select 2023 Chevrolet Bolt EUV. Navigate to Battery Energy Control Module (BECM) and High Voltage Battery Control Module. Perform 'Read DTCs' function and document all present and history codes. Pay particular attention to U0xxx communication codes, P1xxx powertrain codes related to charging, and B10xx body codes related to charge port.
3. 3

   Check charging system enable conditions
   In GDS2, navigate to BECM data display. Monitor the following parameters with vehicle off: Charge Port Status (should show 'Ready'), Onboard Charger Temperature, High Voltage Battery Temperature, Battery State of Charge percentage. Verify all temperatures are within normal range (10-45°C for optimal charging). Confirm no charging inhibit flags are active in data stream.
4. 4

   Perform Level 1 charging acceptance test
   Connect a known-good Level 1 (120V) EVSE to the vehicle charge port. Ensure connection is fully seated and charge port door closes properly. Observe charge port status light should illuminate green. Monitor GDS2 data stream for 'Charge Status' parameter to change to 'Charging Active' within 10 seconds. Verify 'Charger Input Voltage' displays approximately 120V AC and 'Charger Input Current' shows approximately 8-12 amps.
5. 5

   Verify onboard charger operation
   With Level 1 charging active, monitor GDS2 parameters: 'Onboard Charger Output Voltage' should match high-voltage battery voltage (typically 300-400V DC depending on state of charge), 'Onboard Charger Output Current' should show 8-15 amps DC, 'Onboard Charger Power' should display approximately 1.3-1.4 kW. Allow charging to continue for at least 2 minutes while monitoring for stable values and no fluctuations.
6. 6

   Test charge port communication
   While still connected to Level 1 EVSE, navigate to BECM Special Functions in GDS2. Select 'Charge Port Control Module Test' if available. Verify charge port successfully communicates EVSE pilot signal status. Disconnect EVSE and observe that charge status returns to 'Not Charging' within 3 seconds and charge port status light extinguishes.
7. 7

   Perform Level 2 charging acceptance test
   Connect a known-good Level 2 (240V) EVSE to vehicle charge port. Ensure full connection and observe charge port light illuminates. Monitor GDS2 for 'Charger Input Voltage' to display approximately 240V AC. Verify 'Charger Input Current' reaches maximum available amperage based on EVSE rating (typically 16-32 amps). Confirm 'Onboard Charger Power' reaches expected Level 2 charging rate (typically 7.2-11 kW for Bolt EUV).
8. 8

   Monitor thermal management during charging
   With Level 2 charging active for at least 3 minutes, monitor 'Onboard Charger Temperature', 'Battery Coolant Temperature', and 'Battery Thermal Management Status' in GDS2. Verify onboard charger temperature does not exceed 85°C. Confirm battery thermal management system activates if battery temperature rises (indicated by coolant pump and/or HVAC compressor activation on data stream).
9. 9

   Test charging interruption and resumption
   While Level 2 charging is active, disconnect the EVSE from charge port. Verify charging stops immediately and GDS2 shows 'Charge Status' returns to 'Not Charging'. Reconnect EVSE and confirm charging resumes within 10 seconds without requiring vehicle power cycle. This verifies proper charge session management.
10. 10

    Verify charge port locking mechanism
    With EVSE connected and charging active, attempt to remove charge connector from port (it should be locked). In GDS2, navigate to BECM Special Functions and select 'Unlock Charge Port' command. Execute command and verify you can now remove the connector. Reconnect and confirm port automatically locks when charging resumes. This verifies charge port lock actuator operates correctly.
11. 11

    Review charging system data and complete test
    Disconnect EVSE from vehicle. In GDS2, capture and save a data snapshot of all BECM and high-voltage battery parameters. Review all data for values within normal ranges. Check for any new DTCs generated during testing. Document charging acceptance rates for both Level 1 and Level 2, along with all temperatures recorded. Compare charging rates to specifications: Level 1 should be approximately 1.3-1.4 kW, Level 2 should be 7.2-11 kW depending on EVSE capacity.

Reassembly

1. Close charge port door fully and verify it latches securely
2. Disconnect MDI scanner from OBD-II port
3. Clear any non-persistent diagnostic codes if testing confirmed systems operate normally
4. If any DTCs remain or charging rates are below specification, consult GM service information for specific diagnostic procedures

Verification

• Confirm vehicle accepts charge from both Level 1 and Level 2 EVSE without errors
• Verify no new diagnostic trouble codes related to charging system are present
• Ensure charging input voltage and current values match expected values for EVSE type
• Confirm onboard charger output voltage matches battery voltage and output current is appropriate for charging level
• Validate charge port locking mechanism engages and releases properly during charge sessions
• Verify thermal management system activates appropriately during charging
• Document baseline charging performance data for future comparison if charging concerns arise

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