B2CE791 - B2CE791 CUDA No Valid Data

Fault Depth Definition

Fault code B2CE791 indicates a loss of data communication integrity between the vehicle perception system and the central computing unit. In this architecture, CUDA serves as the core data processing node, responsible for receiving and parsing raw signals from peripheral sensors. When the system identifies "CUDA no valid data", it means the control unit failed to receive data frames conforming to protocol standards within the expected communication cycle, or received data with erroneous check bits, preventing blind spot monitoring logic from performing normal target tracking and risk assessment. This fault directly blocks information interaction between the perception layer and decision layer, belonging to communication class or data validity class faults.

Common Fault Symptoms

When this fault code is activated and stored, drivers may observe the following system behavior anomalies:

• Dashboard displays a warning icon indicating that the Blind Spot Monitoring System (BSM) is unavailable or has limited functionality.
• Lane Change Assist function stops working; lack of visual or auditory warnings when vehicles approach from behind or the side.
• In relevant driving assistance settings menu, the blind spot monitoring option turns grey and becomes unselectable.
• After vehicle startup, radar module initialization handshake fails during system self-check phase.

Core Fault Cause Analysis

Based on the potential indication of "Left Rear Millimeter Wave Radar Failure", the root cause can be categorized into the following three technical dimensions:

• Hardware Components: Internal chip damage within the left rear millimeter wave radar sensor, physical damage to the antenna array, or failure in radar module initialization itself, resulting in inability to generate valid signals.
• Wiring/Connectors: Communication bus (such as CAN FD) connecting the radar and CUDA control unit has open circuit or short circuit, or excessive contact resistance at power/ground pins causing signal attenuation, leading to data transmission interruption.
• Controller: Abnormal internal logic processing within the CUDA computing unit, or mismatched configuration parameters between sensor and controller, resulting in valid data being filtered or discarded and not recognized as valid information.

Technical Monitoring & Trigger Logic

The system determines fault validity through continuous monitoring of the data link status:

• Monitoring Target: Focus on monitoring packet validity incoming from CUDA interface, communication heartbeat signals, and data check code (CRC) to ensure signal integrity.
• Trigger Fault Condition: When the vehicle electrical system detects the start switch set in $ON$ gear, the system enters the initialization monitoring phase and begins polling sensor status.
• Set Fault Condition: Within the prescribed monitoring time window, the control unit determines that no valid information is received from CUDA, or multiple communication cycle frames are lost continuously, thereby locking fault code B2CE791 and recording freeze frame data.