BYD ATTO 3 (e-Platform 3.0) C1BA500 EPS ECU Calculation Error

C1BA500 indicates an internal calculation error detected by the electronic power steering (EPS) electronic control unit (ECU). The fault affects EPS control processing, where the ECU evaluates steering inputs, sensor data, motor-control parameters, and network information to determine the required steering assistance. The BYD ATTO 3 uses BYD’s e-Platform 3.0 architecture, with this generation introduced from 2022 and continuing onward.

Symptoms

• EPS or steering warning light illuminated
• Steering may become heavier than normal
• Reduced or lost electric power steering assistance
• Steering system warning message displayed
• Intermittent steering assistance
• EPS-related diagnostic trouble codes stored
• Steering assist may enter a restricted operating mode
• Other communication or control-system warnings may appear

Possible Causes

• Internal EPS ECU calculation or processing error
• EPS ECU software or configuration fault
• Unstable EPS power supply
• Low or excessive system voltage
• EPS ECU memory or internal circuit fault
• Communication error affecting required input data
• Incorrect sensor or steering-angle information
• Damaged EPS ECU connector
• Wiring or power/ground fault
• Internal EPS ECU failure

Diagnosis

Diagnosis should begin by confirming C1BA500 and checking whether additional EPS, voltage, sensor, or CAN communication faults are stored. EPS power and ground supplies, network communication, steering-angle and related sensor data, and ECU operating status should then be evaluated against manufacturer specifications. If external inputs and electrical supplies are correct, manufacturer diagnostic procedures may be required to determine whether software configuration, programming, or an internal EPS ECU fault is responsible. Workshop technicians across New Zealand frequently use factory repair procedures when diagnosing electronic control-module faults like this.

Accurately diagnosing this fault often requires manufacturer testing procedures, wiring diagrams, connector pinouts, specifications, and system calibration information. Access to the factory service manual significantly reduces diagnostic time and helps prevent unnecessary parts replacement.

Applicable Years

2022, 2023, 2024, 2025, 2026, onwards

To order the correct OEM Service and Repair Manual for your BYD ATTO 3, submit your request using the form below and our team will provide the ordering details.