B165D00 - B165D00 Right Front Crash Sensor Not Connected

B165D00 Fault Definition Details

This fault code (B165D00) belongs to the self-diagnosis scope of the Supplemental Restraint System (SRS/Supplemental Restraint System), specifically monitoring the status of the Right Front Positive Collision Sensor. Within the vehicle's safety architecture, the Right Front Collision Sensor is responsible for real-time perception of impact energy and direction applied to the front of the vehicle, converting it into physical signals fed back to the control unit. "Not Connected" refers to the condition where the Airbag Control Unit (SCM/Safety Controller Module) detects an electrical circuit break or missing signal input in that sensor's loop. This fault implies the system cannot acquire critical information regarding frontal impact location and intensity, breaking the existing crash safety feedback loop and directly affecting the response logic determination for right-front passenger compartment impact events.

Common Fault Symptoms

When the Airbag Control Unit confirms the Right Front Collision Sensor is in a non-connected or abnormal signal state, the system will trigger protective mechanisms and provide visual warnings to the driver. Specific driving experience and dashboard feedback may manifest as:

• Airbag System Warning Light On: The SRS indicator light on the dashboard (usually displaying an airbag icon) stays lit or flashes continuously, indicating a system fault.
• Safety Feature Degradation Mode: The vehicle's "Partial Airbag Function Loss" state is activated, meaning that under specific collision conditions, the right-front side airbag may not deploy according to preset logic.
• Vehicle Self-Check Information Recording: The On-board Diagnostic system stores this fault data stream in memory for subsequent repair reading and history record analysis.

Core Fault Cause Analysis

Based on existing diagnostic data, the physical roots leading to the generation of DTC B165D00 can be categorized into three dimensions of hardware or logic anomalies:

• Harness or Connector Failure: The harness connecting the Right Front Collision Sensor to the Control Unit may suffer wear, breakage, compression deformation, or relevant electrical connectors may loosen due to vibration, with terminal corrosion leading to excessive contact resistance or open circuits.
• Right Front Collision Sensor Failure: Core components inside the sensor such as photoelectric elements or acceleration sensing probes suffer physical damage or aging failure, preventing them from outputting normal signal levels to the Control Unit.
• Airbag Controller Failure: Abnormalities occur in the input port circuits within the control unit (e.g., open or short circuit), or the logic module responsible for processing the sensor signal fails, misjudging it as a "Not Connected" state.

Technical Monitoring and Trigger Logic

The Airbag Control Unit identifies sensor connection status through continuous potential monitoring or communication protocols. Its specific monitoring determination logic is as follows:

• Monitoring Target: The system continuously monitors the electrical continuity of the Right Front Collision Sensor loop and signal integrity.
• Fault Setting Condition: When a physical disconnection or non-installed state of the Right Front Collision Sensor is detected, specifically satisfying the condition "Right Front Collision Sensor Not Connected".
• Trigger Logic Flow: During self-check procedures or real-time operation, the Airbag Controller receives a signal indicating the circuit break in the Right Front Collision Sensor loop. Once this signal persists beyond a preset time threshold or meets diagnostic count requirements, the Control Unit writes DTC B165D00, marking the formal generation of the fault.