B1C4071 - Four Door Lock Motors Stall

Fault Depth Definition

DTC B1C4071 (Four-Door Lock Motor Stall) is a specific diagnostic fault code within the Body Network Control System, with its core function centered on monitoring and protecting drive actuators. This fault code primarily maps to the Left Domain Controller's monitoring scope, used to provide real-time feedback on the motor's physical position and rotational speed status during the door lock operation. When the system detects abnormal high current load in the drive circuit, it indicates that the motor may be in a mechanically stuck or stall condition due to excessive load. This definition clarifies the control logic for torque feedback from the actuator managed by the control unit, aiming to prevent circuit overheating damage and excessive battery drainage caused by prolonged overloads.

Common Fault Symptoms

According to the fault occurrence symptoms (Four-Door Lock Motor Failure), the vehicle may present the following feedback in the dashboard diagnostic system and actual driving experience:

• The vehicle cannot achieve normal door locking and unlocking operations through physical switches, remote keys, or keyless entry systems.
• The central screen or Body Control Module prompts "Four-Door Lock System" electrical fault warning information.
• The internal status light within the Left Domain Controller may turn on, indicating that the relevant actuator has triggered a fault record.
• In extreme cases, due to continuous high current draw, it may cause abnormal voltage fluctuations in the whole vehicle's low-voltage electrical system.

Core Fault Cause Analysis

Combining possible causes from the original data, the technical root is structurally analyzed from three dimensions:

1. Hardware Components (Four-Door Lock Motor Failure) The motor's internal winding may have a short or open circuit, leading to loss of electromagnetic torque; or mechanical structures such as gears and rails become stuck, causing the motor to rotate abnormally under load, thus producing physical stall signals.

2. Wiring/Connectors (Harness or Connector Failure) There is a risk of abnormal short circuit in the power positive/negative harnesses connecting the motor and controller, or resistance values change drastically due to poor contact, interfering with the control unit's accurate identification of current status; connector pin corrosion or loosening can also cause circuit impedance fluctuations.

3. Controller (Left Domain Controller Failure) The control unit responsible for logic operations may have software logic errors or hardware damage in its internal drive module, leading to misjudgment of the sampled current signal values, and incorrectly triggering stall judgment conditions.

Technical Monitoring and Trigger Logic

The system's diagnostic logic is based on strict electrical parameter thresholds, with the trigger mechanism as follows:

• Monitoring Target: The Left Domain Controller collects and analyzes control circuit current in the Four-Door Lock Drive circuit in real-time.
• Numerical Range Standard: The system set fault judgment threshold is detecting control circuit current ≥$20\text{A}$. If instantaneous or continuous current exceeds this standard, the system will mark it as an abnormal state.
• Specific Operating Conditions: Faults are triggered only during Four-Door Lock Operation. The system enables real-time monitoring during active motor drive for locking or unlocking actions; during vehicle static sleep or non-operating states (e.g., ignition off), this threshold judgment is not performed. This dynamic monitoring ensures that DTC B1C4071 is recorded only when the actuator load runs abnormally.