B18E771 - B18E771 B18E771 Driver Seat Fan Assembly Stall

B18E771 Fault Depth Definition

Fault code B18E771 represents "Driver Seat Fan Assembly Stall". This DTC (Diagnostic Trouble Code) is primarily triggered by the Left Domain Controller when monitoring the driver seat ventilation system. In this vehicle's electrical architecture, the driver seat cooling function depends on real-time communication and load monitoring between the drive motor, power supply wiring, and control unit. When the system detects mechanical jamming or electrical overload in the fan assembly, causing the motor to fail to rotate normally or have severely limited speed, the system determines a "stall" state. This fault code reflects the control unit's abnormal recognition of the feedback loop for actuator physical position and rotation status, belonging to the domain controller's active protection mechanism against seat component health status.

Common Fault Symptoms

When B18E771 fault code is recorded and relevant indicator lights illuminate, the vehicle exhibits specific driving experience degradation phenomena. Car owners can perceive typical symptoms including but not limited to:

• Cooling Function Interruption: Driver seat ventilation area stops blowing air, causing complete failure of cooling function for the driver inside the vehicle.
• Abnormal Noise Feedback: Under certain conditions, attempting to start ventilation may be accompanied by abnormal noise from motor overload or a jamming sound.
• Instrument Warning Messages: Central control screen or instrument cluster may display "Seat Heating/Ventilation Fault" or general vehicle control unit alarm information.
• Functional Self-Lock Protection: To protect motor circuit, Left Domain Controller may automatically cut off output power to this fan assembly until fault is reset.

Core Fault Cause Analysis

Based on diagnostic logic provided by original data, generation of this fault mainly attributes to physical or electronic reasons in following three dimensions:

• Hardware Component Abnormality: Driver Seat Assembly Failure. This refers to coil short circuit inside seat ventilation motor, mechanical structure jamming (foreign object entering air duct causing excessive shaft resistance) or damaged fan blades, directly causing motor failure according to instructions.
• Wiring/Connector Faults: Harness or Connector Failure. Involves open/short circuit in power supply wiring between Left Domain Controller and Driver Seat Assembly, or loose intermediate connector/pin withdrawal causing high contact resistance, resulting in ineffective drive current monitoring or voltage abnormalities.
• Controller Logic Computation Fault: Left Domain Controller Failure. Internal logic errors in control unit responsible for processing motor control instructions, such as damaged sampling circuit failing to correctly interpret current signals, or abnormal execution of control strategies.

Technical Monitoring & Trigger Logic

This fault code determination follows strict real-time monitoring algorithms, requiring simultaneous satisfaction of following operating conditions and parameter thresholds:

1. Fault Setting Conditions

   • Monitoring Target: Drive motor circuit current.
   • Trigger Criterion: Drive current $>10A$ continuously collected for $3s$.
   • Note: This parameter is system preset protection threshold; time window and current upper limit both support configuration, aiming to exclude transient interference and ensure sustained overload.

2. Trigger Fault Conditions Determination of above setting conditions takes effect only when following system states hold true simultaneously:

   • Voltage Range: System supply voltage stabilized in normal range $9V$~$16V$.
   • Power Status: Vehicle in ON Key Power (ignition switch on or battery management allows supply) mode.
   • Function Activation: Driver operation interface instruction indicates Driver Seat Ventilation is in Working State.

Once above all conditions are met and current continuously exceeds $10A$ limit, Left Domain Controller will record this fault code and enter corresponding fault processing state.