B1CE613 - B1CE613 Rear Fog Lamp Drive Circuit Open Circuit Fault

Fault Depth Definition

B1CE613 is defined as Rear Fog Lamp Drive Circuit Open fault (Rear Fog Lamp Drive Circuit Open). In automotive electronic architecture, this DTC indicates an electrical continuity interruption or open circuit state between the control unit and the rear fog lamp load. The vehicle's Left Domain Controller is primarily responsible for monitoring and managing this. Its core function lies in real-time detection of current feedback signals within the drive loop. When the system executes the command to light up the rear fog lamp, the control unit expects to collect corresponding current consumption data on the load side. If the control logic determines that the drive loop fails to form an effective closed path and continues to monitor open circuit characteristics, this fault code is triggered. This definition clarifies that the fault occurs on the drive path from power output to load (rear fog lamp), not just a simple lamp burnout, typically involving infinite line impedance or no electrical connection on the load side.

Common Fault Symptoms

When vehicle enters specific driving states, drivers and onboard systems observe the following distinct phenomena:

• Instrument Illumination Function Failure: Under the condition of turning on low beams then activating rear fog lamp switch, the rear fog lamp module at vehicle tail cannot receive effective drive signal, manifested as lamp not lighting at all.
• System Monitoring Anomaly Records: Vehicle control strategies continuously collect non-expected electrical characteristics, generating B1CE613 mark in fault logs, possibly accompanied by relevant indicator lamp warnings on dashboard (depending on specific model configuration).
• Function Response Delay or Missing: Rear fog lamp switch command signal has been received, but execution end does not produce corresponding physical light output feedback.

Core Fault Cause Analysis

According to system diagnostic logic, triggering of B1CE613 DTC mainly attributes to potential problems in following three dimensions:

• Hardware Component Abnormality: Damage inside rear fog lamp assembly causing filament or LED module open circuit, making current unable to form loop.
• Wiring and Connector Faults: Harness physically broken between domain controller and rear fog lamp, insulation layer damaged, or related connectors poor contact, pin loosening, causing high impedance or open circuit state.
• Controller Logic Anomaly: Internal circuit damage of drive output module inside Left Domain Controller, or control algorithm misjudgment that drive current cannot be established, belonging to control unit level functional fault.

Technical Monitoring and Trigger Logic

Generation of this DTC is based on strict electrical parameter monitoring and time threshold determination, specific trigger conditions and monitoring targets are as follows:

• Monitor Target Parameters

  • Drive Current: System real-time collects current value flowing through rear fog lamp drive circuit.
  • Controller Voltage: Monitors stable voltage state of control unit power supply port.

• Numerical Judgment Thresholds (LaTeX Format)

  • Time Condition: Within duration satisfying all setting conditions, need to continuously collect drive current as $0$ for $3s$.
  • Voltage Range: Controller supply voltage must be between $9V \sim 16V$, ensuring monitoring occurs within normal operation power window.

• Specific Operating Conditions

  • Power State: Vehicle switch position needs to be at "ON" gear, ensuring whole vehicle electrical system activated.
  • Load Configuration State: Must satisfy “Rear Fog Lamp On” command output condition (i.e., driver has turned on fog lamp switch).
  • Architecture Compatibility: Applies only to R1 Platform.
  • Tail Light Configuration Logic: Trigger judgment based on one of following two configurations: Tail light configuration without LIN communication, or tail light configuration with LIN communication where rear fog lamp integrated into rear tail light control domain.

• Fault Judgment Closed Loop When satisfying all above settings and voltage within $9V \sim 16V$ interval, if control unit continues to monitor current value as $0$ time window exceeds $3s$, system immediately judges as drive circuit open fault (B1CE613) and locks this state to prevent invalid command output.