U111982 RCR_R Counter Error: System Technical Specification Document

Fault Depth Definition

U111982 RCR_R Counter Error is a critical diagnostic code in vehicle electronic control architecture, primarily used to indicate synchronization anomalies in the data interaction link between the right-rear millimeter-wave radar system and the main control unit. In the longitudinal control logic of the Adaptive Cruise Control System (ACC), this fault code reflects that the controller failed to verify expected data frame counts or communication protocol sequence numbers when processing feedback information from the mmWave radar sensors. When the monitoring timer detects continuous packet loss or checksum errors, the system determines a counter anomaly. This definition clarifies the fault's role in the vehicle Electronic Electrical Architecture: it is a low-level logic verification mechanism ensuring the integrity of the ADAS perception closed loop, aiming to prevent longitudinal vehicle speed control deviations caused by inaccurate signal transmission.

Common Fault Symptoms

When the system records and stores U111982 RCR_R Counter Error, the vehicle may provide the following perceptible experience changes to the driver:

• Adaptive Cruise Function Failure: The ACC system may fail to activate completely or exit running mode shortly after activation, with the system indicator light turning on.
• Dashboard Warning Prompts: Fault icons related to radar systems or ADAS may flash or remain lit on the central display or instrument cluster.
• Vehicle Speed Control Limitation: Due to the interruption of the sensor feedback loop, the vehicle may limit maximum speed to ensure safety redundancy or fail to maintain the set target cruise speed.
• System Status Light On: Some models may retain fault status indicator signals when detecting this DTC via diagnostic mode or service tools.

Core Fault Cause Analysis

According to technical logic, the root causes leading to this counter error can be classified into three dimensions of systemic anomalies:

• Hardware Component Failure: Physical damage occurs to core sensing elements or signal processing units within the right-rear mmWave radar system, preventing effective count feedback signal generation.
• Wiring and Connector Issues: The physical link connecting the controller and mmWave radar experiences open circuit, short circuit, or excessive contact resistance, interrupting pulse signal transmission at the physical layer and preventing accurate parsing.
• Controller Logic Computation Error: Software logic responsible for processing radar data streams within the control unit deviates, failing to correctly identify valid counting information from sensors, leading to misjudgment of hardware failure.

Technical Monitoring and Trigger Logic

The control unit determines and stores U111982 RCR_R Counter Error based on strict electronic monitoring strategies, specific monitoring thresholds and trigger conditions are as follows:

• Monitoring Target: The system continuously monitors feedback signal integrity, data frame sequence numbers, and communication bus status from the right-rear mmWave radar.
• Power Supply Voltage Range: This fault determination is executed only when the controller operating voltage is within the effective range of $9V$~$16V$, ensuring effective diagnostic sampling during vehicle electrical system fluctuations.
• Timing Trigger Conditions:
  • Initialization Monitoring: After power-up initialization for 3s, diagnostic logic enters active monitoring state.
  • Fault Determination Threshold: A single monitoring timer error must fail consecutively 3 times before the system ultimately confirms and sets this fault code.
• Network and Status Conditions:
  • Bus Status: Public CAN (Controller Area Network) is not in bus-off state, ensuring physical connection of communication network exists and is not fully offline.
  • Mode Limitation: Triggers only when Factory Mode is off (i.e., vehicle is in normal user operation status), avoiding false reports during development or testing phases.
  • External Interaction Signals: System does not receive BCM (Body Control Module) power-down notification, indicating stable power supply status and normal operation mode.
  • Detection Interval Timer: After the server detects DTC, a delay of 3s is required to confirm continuity and stability of fault signal, preventing false reports caused by transient interference.