B1E0107 - B1E0107 Previous Channel Switch Stuck Fault

B1E0107 Fault Code Definition

In vehicle Audio and Navigation (AVN) control system architecture, Fault Code B1E0107 is defined as "Previous Channel Switch Stuck". This code indicates an abnormal persistent state feedback received by the Input Signal Processing Module. Specifically, the "Previous Channel Switch", as part of the user interaction interface, is essentially a physical position sensor or momentary pulse generator, intended to provide authentic channel switching instructions to the Central Control Unit. When the system determines the switch is in a "Stuck" state, it means the input signal detected by the control unit failed to correctly reset to the initial level, or remained above the activation threshold after operation, causing the system to mistakenly believe the user continuously requests backward audio track switching. This fault code directly relates to the input validation loop in HMI logic, indicating state desynchronization between the physical actuator and the signal decoding circuit, potentially affecting normal navigation functions of the multimedia system.

Common Fault Symptoms

Vehicle owners might observe the following dashboard feedback or system response anomalies during driving, including specific manifestations:

• No Response to Previous Channel Operation: When the driver presses the physical "Previous Channel/Track" button, the center display or audio source shows no state change, and the expected track rewind is not achieved.
• Interface State Locked: In some vehicle models, the control unit may mark the current channel as unchangeable or continuously highlight the switching icon on the UI without being able to exit the active state normally.
• Function Logic Failure: Because the system determines the switch signal abnormally occupies resources, it may cause related audio source selection logic to pause until the control unit resets or enters a fault-safe mode.
• System Warning Light Illuminated: If the vehicle is configured with a related fault indicator light (e.g., "Please Check Multimedia"), it may be accompanied by an indicator lamp indicating communication or status anomalies in the input module.

Core Fault Cause Analysis

Based on diagnostic data B1E0107, the potential fault sources are analyzed based on three dimensions of control link logic:

• Hardware Component (Switch Actuator): This is the core source of fault determination. The physical contact leaf springs inside the "Previous Channel Switch" may deform, stick or increase mechanical resistance, causing the button to return to the electrical neutral position after pressing. This mechanical "Stuck" directly triggers signal level monitoring within the control unit, identifying it as a persistent error high level (Stuck High).
• Wiring and Connectors (Signal Transmission Path): Although the root cause is switch sticking, if the wiring to the audio control unit has insulation damage, excessive contact resistance or loose soldered connectors, voltage fluctuations or signal jitter may occur during switch action, causing the control unit to erroneously judge the signal as not resetting normally.
• Controller (Logic Operation Module): The audio system's control software must real-time parse input pin voltage status. If the controller's signal sampling frequency or fault determination threshold algorithm has a bias, it may incorrectly delay response to normal transient signals, thus triggering this specific "Stuck" fault code. However, in this dataset, hardware sticking is prioritized as the first explanation.

Technical Monitoring & Trigger Logic

The system validates and locks the fault state through specific operational conditions. Specific monitoring flow is as follows:

• Trigger Pre-conditions: Fault determination occurs only during the running mode with Ignition Switch in ON Position. In vehicle sleep or Off mode states, the control unit usually does not activate high-frequency polling logic for this input signal, so fault code generation verification cannot be completed.
• Monitoring Target Parameters: The control unit continuously monitors the physical feedback state (Switch Feedback State) of the previous channel switch, focusing on whether the signal voltage jumps within an expected range during effective operation. Monitoring focuses on identifying if the signal remains at the activation level for a long time without returning to baseline.
• Fault Determination Logic: After the driver executes the action of operating the previous channel switch, the system is expected to observe signal release or reset within a specific sampling cycle. If the control unit continuously detects input signals maintaining an abnormal state (Signal Remain Abnormal), and does not receive a reset signal within a predetermined timeout, it satisfies the determination condition for "Previous Channel Switch Stuck Fault", thereby storing B1E0107 and illuminating related fault indicator lights.