B11BD19 - B11BD19 LIN1 Ambient Light Driver Overload Fault

meaning abnormal instantaneous or continuous power on the LIN1 ambient light supply pin during electrical energy transmission.

H3 Common Fault Symptoms

After the system records B11BD19 DTC and triggers protection logic, drivers and passengers can perceive the following driving experience and instrument feedback:

• Illumination Function Failure: Interior ambient lighting sources cannot light up normally; even with the switch open, LED modules in corresponding areas remain off.
• Color Adjustment Obstructed: Color change commands issued by the central control system or touch buttons cannot be executed; light brightness locks at the pre-fault state or defaults to fully off.
• Dynamic Response Abnormality: After entering specific operating conditions, normally smooth gradient color adjustment functions are interrupted, possibly appearing as lamp flickering or direct extinction anomalies.

H3 Core Fault Cause Analysis

Based on technical logic derivation, this fault may be caused by hardware or logic anomalies in the following three dimensions:

1. Load Component (Lamp) Abnormality: Internal LED chips or constant current drive circuits of the Left Rear Door Ambient Light occur short circuits or performance degradation, causing increased current consumption exceeding the control unit's output capability.
2. Wiring and Connector Failure: Physical poor contact of harnesses or connectors, insulation layer damage causing ground short circuits, or connector pins squeezed/deformed, triggering abnormal loop impedance decrease, thereby triggering overcurrent protection.
3. Controller End Logic Abnormality: Sensors responsible for LIN1 ambient light supply pin current sampling inside the Left Domain Controller drift, or power devices (such as MOSFETs) in the drive circuit are struck through, causing the control unit to misjudge the overload status.

H3 Technical Monitoring and Trigger Logic

The trigger mechanism of this DTC is based on dynamic acquisition and algorithmic judgment by the control unit of real-time electrical parameters; specific monitoring targets and logic are as follows:

• Monitored Target Parameters: The system primarily monitors drive current and supply loop voltage.
• Current Threshold Judgment: The controller must continuously acquire drive current values meeting $ \ge 5A $ at the same point in time, complying with "current value matching" hardware feature codes to ensure signal authenticity and repeatability.
• Time Window Logic: The aforementioned overcurrent state must persist for at least $ 3s $ (continuous 3 seconds) to rule out instantaneous pulse interference or false alarms from unstable operation.
• Operating Condition Trigger: Fault judgment is executed only within the valid power supply range of the Controller Voltage being $9V \sim 16V$, while also requiring the LIN1 Ambient Light Supply Pin to be in a working power state. If voltage is below $9V$ or above $16V$, the system treats this as a non-normal working interval and freezes fault judgment logic.

Cause Analysis** Based on technical logic derivation, this fault may be caused by hardware or logic anomalies in the following three dimensions:

1. Load Component (Lamp) Abnormality: Internal LED chips or constant current drive circuits of the Left Rear Door Ambient Light occur short circuits or performance degradation, causing increased current consumption exceeding the control unit's output capability.
2. Wiring and Connector Failure: Physical poor contact of harnesses or connectors, insulation layer damage causing ground short circuits, or connector pins squeezed/deformed, triggering abnormal loop impedance decrease, thereby triggering overcurrent protection.
3. Controller End Logic Abnormality: Sensors responsible for LIN1 ambient light supply pin current sampling inside the Left Domain Controller drift, or power devices (such as MOSFETs) in the drive circuit are struck through, causing the control unit to misjudge the overload status.

H3 Technical Monitoring and Trigger Logic

The trigger mechanism of this DTC is based on dynamic acquisition and algorithmic judgment by the control unit of real-time electrical parameters; specific monitoring targets and logic are as follows:

• Monitored Target Parameters: The system primarily monitors drive current and supply loop voltage.
• Current Threshold Judgment: The controller must continuously acquire drive current values meeting $ \ge 5A $ at the same point in time, complying with "current value matching" hardware feature codes to ensure signal authenticity and repeatability.
• Time Window Logic: The aforementioned overcurrent state must persist for at least $ 3s $ (continuous 3 seconds) to rule out instantaneous pulse interference or false alarms from unstable operation.
• Operating Condition Trigger: Fault judgment is executed only within the valid power supply range of the Controller Voltage being $9V \sim 16V$, while also requiring the LIN1 Ambient Light Supply Pin to be in a working power state. If voltage is below $9V$ or above $16V$, the system treats this as a non-normal working interval and freezes fault judgment logic.