B222401 - B222401 Sun Visor Motor Hall Signal Abnormal

B222401 Sunshade Motor Hall Signal Abnormality Detailed Explanation

### Fault Definition Depth

B222401 Sunshade Motor Hall Signal Abnormality (DTC: B222401) is the standard diagnostic definition in which the Right Domain Controller within the vehicle's intelligent electronic architecture detects a deviation in the internal actuator feedback loop. In the electric sunshade system, the Hall Sensor is integrated inside the motor to monitor the physical position and rotational speed of the armature in real time, providing high-precision position coding signals to the control system. The core definition of this fault code points to interruption or distortion of information interaction between the control unit and the actuator. When the Right Domain Controller performs dynamic logic calculations and finds that the received Hall feedback signal voltage value exceeds the preset normal operating threshold, the system determines "abnormality" and generates this fault code to record data stream deviations in the electrical system, ensuring driving safety and functional integrity. This definition covers the complete signal link status assessment from the motor side sensor to the controller input port.

### Common Fault Symptoms

When the system determines that fault code B222401 exists, car owners may observe the following specific phenomena during actual driving:

• Sunshade Function Failure: The sunshade on the Right or Left domain cannot move up and down normally, manifesting as the motor running but mechanically stopping or no action at all.
• Instrument Panel Warning Prompt: The vehicle information center display screen may show text prompts such as "Sunshade Malfunction" or "Electrical System Error".
• Function Restricted Mode Activation: For safety, the control system may lock the sunshade in its current position, prohibiting manual or automatic operation instructions from being executed.
• Abnormal Motor Sound: When attempting to trigger sunshade movement, a humming sound from the motor without displacement feedback may occur, indicating signal conflict at the load end.

### Core Fault Cause Analysis

For technical analysis of this fault code, troubleshooting needs to be conducted from the following three hardware and logic dimensions, all based on the control unit's validation logic for input signals:

• Hardware Component (Sunshade Motor): The Hall sensor element inside the motor may produce distorted output signals due to overheating, vibration, or physical aging. In addition, if the motor power winding is open or short-circuited, it will directly raise or lower the Hall voltage detection point, causing the controller received value to exceed the threshold range.

• Wiring and Connectors (Physical Connection): The wiring harness connecting the sunshade motor to the Right Domain Controller may experience ground short circuit due to insulation layer wear, or high contact resistance caused by connector pin oxidation or loosening. Such physical connection abnormalities will cause attenuation or distortion of Hall signals during transmission, affecting the accuracy of voltage signals.

• Controller (Logic Calculation): The Right Domain Controller, as a core unit for signal acquisition and processing, may fail in its internal circuit responsible for monitoring Hall signals. If the ADC (Analog-to-Digital Converter) sampling accuracy of the controller decreases or the internal threshold setting logic is wrong, even if the external line is normal, the system will incorrectly determine the received voltage to be in an abnormal state.

### Technical Monitoring and Trigger Logic

The triggering of this fault code follows strict electrical parameter monitoring protocols, aimed at precisely identifying signal quality boundary values:

• Monitoring Target: The Right Domain Controller monitors the Hall Signal Voltage input to the sunshade motor drive circuit in real time. The system focuses on analyzing whether the voltage level in the feedback loop is within the control-allowable logic level range.

• Numerical Range Determination: According to diagnostic logic, when the monitored Hall signal voltage value is below $9V$ or above $16V$, the system will trigger fault determination. The specific abnormal threshold interval is: $9V$~$16V$. Any voltage fluctuation deviating from this range is considered an invalid signal input, which may cause the fault code to light up.

• Specific Trigger Condition: This monitoring does not run statically all day and night, but is dynamically activated when the Right Domain Controller drives the sunshade motor. Only during the period when the control unit issues instructions and attempts to adjust the sunshade position will the system sample and compare the real-time feedback of the Hall signal at a high frequency. If under this specific dynamic working mode the signal continuously or instantaneously deviates from the normal voltage interval of $9V$~$16V$, the fault condition is met, thereby recording B222401 fault data frame.