BYD ATTO 3 (e-Platform 3.0) C121200 Camera Obstruction

C121200 indicates that a camera used by the vehicle’s driver assistance system has detected an obstruction or an unacceptable viewing condition. The fault affects the camera-based sensing system responsible for providing visual information to functions such as driver assistance and safety monitoring. The BYD ATTO 3 uses BYD’s e-Platform 3.0 architecture, with this generation introduced from 2022 and continuing onward.

Symptoms

• Driver assistance warning displayed
• Camera obstruction warning message
• Driver assistance functions may become temporarily unavailable
• Lane-related assistance may be restricted
• Camera-based safety functions may be disabled
• Fault may occur intermittently
• C121200 stored in the relevant control system
• System may return to normal after the camera view is restored

Possible Causes

• Dirt, dust, mud, or road film covering the camera
• Condensation or moisture affecting the camera view
• Ice, snow, or other environmental contamination
• Windscreen obstruction near the camera
• Damaged or incorrectly positioned camera
• Windscreen replacement or installation issue
• Camera mounting or alignment problem
• Camera lens contamination
• Electrical or communication fault affecting the camera
• Camera calibration or configuration issue

Diagnosis

Diagnosis should begin by confirming C121200 and identifying which camera or sensing function has reported the obstruction.

The camera lens and viewing area should be inspected for contamination, moisture, physical damage, or obstructions, followed by checks of camera status, power supply, communication, mounting position, and calibration requirements against manufacturer specifications.

If the fault remains after the viewing area is clear, further diagnostic testing is required to distinguish an optical obstruction from an electrical, alignment, or camera-module fault. For New Zealand owners, confirming the cause before replacing or recalibrating the camera can help avoid unnecessary repair costs.

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.