C1B8500

Electric power steering controller: CAN bus off

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Severity varies by vehicle — Critical (4): Denza N7 2025, Denza N9, Destroyer 05, Qin Plus; Warning (21): BYD D1 2023, BYD Overseas DOLPHIN 2025, BYD Overseas SEAL 2025, BYD Qin L 2024-2025, BYD Seagull 2023, BYD Seagull 2025, BYD Seal 2023, BYD Seal 2025, BYD Sealion 07 2024, BYD Song L DM-i 2025, BYD Song L EV 2024, BYD Song PLUS 2021, BYD Song Pro DM-i 2022-2023, BYD Tang NEV 2021, BYD Tang NEV 2022, BYD Tang NEV 2023, BYD Tang NEV 2023 EV, Denza D9 EV 2023, Denza D9 EV 2024, Denza N7 2023, Denza N7 2024.

Before working on any high-voltage component, carry out BYD's high-voltage shutdown: switch the vehicle off, disconnect the 12 V supply and the high-voltage connector, then leave the vehicle for at least 5 minutes before touching orange cabling. Wear insulated gloves and footwear. Do not work on the high-voltage system without training for that vehicle.

What are the symptoms of C1B8500?

  • Steering system warning lamp stays on
  • Part of the electric power steering stops working

What causes C1B8500?

Ordered by how many BYD-group vehicles list each cause for this code — not by how likely it is on your car.

  • Wiring or connector fault — listed on 52 vehicles
  • CAN network or CAN wiring fault (open or short circuit) — listed on 49 vehicles
  • Electric power steering controller fault — listed on 41 vehicles
  • Fault in another CAN module or its wiring — listed on 26 vehicles

Where do I start with C1B8500?

Check the electric power steering controller DTCs

The full procedure for your vehicle

Sign in and the page continues: the steps in order for your exact vehicle, the values to measure, and the wiring diagrams behind each one.

Worth knowing

  • BYD's high-voltage procedure calls for disconnecting the 12 V supply and waiting at least 5 minutes after shutdown before work begins.

Which vehicles does C1B8500 affect?

  • BYD D1 2023
  • BYD Han DM 2023
  • BYD Han EV 2022
  • BYD Han EV 2023
  • BYD Han L DM 2025
  • BYD Overseas DOLPHIN 2025
  • BYD Overseas M6(RHD) eMAX 7 2025
  • BYD Overseas SEAL 2025
  • BYD Overseas SEALION 07 2025
  • BYD Overseas Song Plus 2024
  • BYD Qin L 2024-2025
  • BYD Seagull 2023
  • BYD Seagull 2025
  • BYD Seal 05 DM-i 2025
  • BYD Seal 06 2025
  • BYD Seal 2023
  • BYD Seal 2025
  • BYD Seal DM-i 2024
  • BYD Sealion 07 2024
  • BYD Sealion 07 2025
  • BYD Song L 2024 4668
  • BYD Song L DM-i 2025
  • BYD Song L EV 2024
  • BYD Song PLUS 2021
  • BYD Song PLUS 2025
  • BYD Song Pro DM-i 2022-2023
  • BYD Tang L 2025
  • BYD Tang NEV 2021
  • BYD Tang NEV 2022
  • BYD Tang NEV 2023
  • BYD Tang NEV 2023 EV
  • BYD Xia 2025-2026
  • BYD Yuan UP 2024
  • Denza D9 DM 2022
  • Denza D9 DM 2025
  • Denza D9 DM-i 2024
  • Denza D9 DM-i 4-Seat 2023-2024
  • Denza D9 EV 2023
  • Denza D9 EV 2024
  • Denza D9 EV 2025
  • Denza D9 EV RHD 2025
  • Denza N7 2023
  • Denza N7 2024
  • Denza N7 2025
  • Denza N8 2023
  • Denza N9
  • Denza Z9 2025
  • Destroyer 05
  • Fangchengbao Bao 5 2023
  • Fangchengbao Bao 5 2025
  • Fangchengbao Bao 8 2025
  • Fangchengbao Titanium 3 2025
  • Qin Plus
  • Yangwang U7 2025
  • Yangwang U8 2023
  • Yangwang U8 2024
  • Yangwang U9 2025

Background reading

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