BYD EV U029800

BMS Communication Fault

Battery Management System not responding.

  • Symptoms: Battery warning lights, reduced power mode.
  • Likely causes: BMS ECU fault or CAN bus interruption.
  • Severity: High
Diagnosis checklist
  • Confirm the code and record freeze-frame data if available.
  • Inspect connectors, wiring harnesses, and grounds related to the affected module.
  • Check fuses, relays, and power supply to the module.
  • Verify CAN/LIN communication integrity and look for related codes.
Recommended actions
  • Clear the code and perform a short road test to confirm recurrence.
  • If the code returns, test wiring continuity and connector pins.
  • Update or replace the affected module if power and communication are normal.
  • For critical warnings, stop driving and arrange service immediately.