U01D829 - U01D829 CMRR ADAS Core System Analyzed Abnormal Data

Fault Code Definition

Fault code U01D829 indicates that the CMRR ADAS core system identifies logical anomalies or unreliable states in key input parameters during multi-source data fusion analysis. This fault code involves the internal data validation mechanism of the Advanced Driver Assistance System (ADAS), indicating that the control unit cannot construct a reliable environmental model based on the currently received sensor information. In this context, the system core logic unit (DAcore) continuously monitors the consistency of data streams; when key dynamic parameters deviate from expected physical models, it is determined as core system abnormality analysis, thereby recording this communication or logic fault.

Common Fault Symptoms

When the vehicle control unit stores fault code U01D829, drivers may perceive the following changes in driving experience or instrument feedback:

• Dashboard displays warning for Blind Spot Monitoring System (BSD) unavailable or function restricted.
• Blind Spot Monitoring System function fails, unable to detect and alarm vehicles on side and rear.
• ADAS related functions may enter degraded mode accompanied by specific fault indicator lights lighting up.
• Center screen may prompt that driver assistance system is temporarily unavailable.

Core Fault Cause Analysis

Based on system architecture and data flow logic, the causes of this fault can be categorized into the following three technical dimensions:

• Hardware Component: Left-rear millimeter wave radar failure is the main physical trigger. The sensor may have physical damage, internal chip failure, or calibration deviation, resulting in abnormal original data output and unable to provide effective target detection information.
• Line/Connector: Public CAN communication link has interference, impedance anomaly, or connector contact poor. Physical connection instability affects data transmission integrity, causing validation errors or packet loss in data received by DAcore.
• Controller: DAcore (data analysis core) logic unit detects values exceeding credible range when processing key parameters. Specifically involves tire size, yawrate compensation and target data logical conflict, leading the system to judge the data as unreliable.

Technical Monitoring and Trigger Logic

The system triggers fault code storage through specific pre-conditions and logic judgments, with specific monitoring targets and operating conditions as follows:

• Monitoring Target: System real-time monitors the credibility of tire size data received by DAcore, yaw rate compensation data, and radar target data.
• Values and State Range:
  • Diagnostic start condition is after bus initialization $3s$.
  • Public CAN does not enter busoff state or busoff recovery $1S$.
• Specific Conditions:
  • Start switch in ON position.
  • Factory mode turned off.
  • Trigger fault judgment when any of the following conditions are met:
    • DAcore detects unreliable tire size data.
    • DAcore detects unreliable yawrate compensation data.
    • DAcore detects unreliable target data.