C113017 - C113017 Left Actuator Power Supply Overvoltage Fault

Fault Depth Definition

C113017: Left Actuator Supply Overvoltage Fault

This DTC points to critical power management logic within the Electronic Parking Brake (EPB) control network. In the vehicle architecture, the actuator in the left rear wheel area (Left Actuator) is responsible for physically locking and releasing brake pads, relying heavily on stable voltage input. When the power monitoring circuit integrated within the Rear Domain Controller detects abnormal high voltage in the wiring harness loop supplying the left actuator, the system judges it as a "supply overvoltage" fault.

This fault not only involves simple voltage amplitude exceeding limits but is also associated with physical position signal feedback between the on-board power assembly and the drive motor. The code indicates that the control unit has identified input voltage to the actuator exceeding safety thresholds, triggering protective logic to prevent coil damage from overcurrent or burning out internal electronic components. In terms of diagnostic hierarchy, this belongs to a high-severity fault, directly affecting the vehicle braking system's active safety management function.

Common Failure Symptoms

When the C113017 DTC is recorded and activated, drivers and on-board instrument systems present the following perceptible phenomena:

• Electronic Parking Function Failure: The dashboard displays the EPB (Parking Brake) indicator light staying on or flashing. The vehicle cannot execute handbrake lock or unlock operations.
• System Enters Protection Mode: The Rear Domain Controller may cut power output to the left actuator, resulting in insufficient parking force after the vehicle stops, posing a risk of rollback.
• Diagnostic Data Stream Anomalies: When reading via a dedicated diagnostic tool, it can be observed that the left actuator supply voltage value continuously exceeds the preset threshold, and the status flag bit is "Fault".
• Instrument Warning Feedback: The center console may display general warning icons related to the braking system, prompting the driver to check the vehicle's braking system status.

Core Failure Cause Analysis

Based on raw data and system architecture logic, this fault can be summarized into the following three-dimensional potential physical root causes:

1. Hardware Components (Actuator & Power Module) Mainly involves On-Board Power Assembly. If the voltage regulation circuit inside the assembly fails, or its output voltage regulation capability declines, it may cause abnormal increase in output voltage pulse peak. Additionally, if the input port protection diode inside the left actuator breaks down and shorts, it may feed high voltage back to the controller end, causing false reports.

2. Wiring & Connectors (Physical Connection) Although raw data does not list wiring issues directly, the power supply path between "On-Board Power Assembly" and "Rear Domain Controller" belongs to typical electrical circuits. Poor grounding caused by damaged insulation layer of wires in this circuit, or large voltage drop fluctuations caused by excessive contact resistance from oxidized connector terminal contact, may interfere with the control unit's judgment logic on voltage stability.

3. Controller (Logic Operation) Rear Domain Controller, as the processing core, if its internal A/D conversion circuit drifts, or the power management chip's threshold comparator ages hard, may trigger fault signals mistakenly under non-overvoltage conditions. Additionally, if controller software calibration parameters do not match the current hardware platform, it may affect the accuracy of judging overvoltage conditions.

4. Energy Supply Source (Power Input) Raw data clearly points out Lead-acid Starter Battery failure as one of the possible causes. When battery voltage is unstable, charging system rectifier diode fails or generator output voltage surges abnormally, this high voltage will conduct directly to on-board bus, keeping actuator supply end continuously in overvoltage state.

Technical Monitoring and Trigger Logic

The control unit continuously monitors input-side voltage of left actuator during operation. Its fault determination algorithm follows specific operating conditions and numerical thresholds:

• Monitoring Target System collects busbar voltage ($V_{in}$) supplying left actuator in real-time, and dynamically compares it with preset safety baseline.

• Trigger Condition Numerical Range According to original setting data, specific logic for fault determination is as follows:

  • Voltage Threshold: The detected instantaneous supply voltage must strictly exceed $16V$. If system detects peak exceeding this value, it considers entering abnormal high voltage area.
  • Duration: The overvoltage state above mentioned is not caused by transient jitter, must be sustained duration $\geq 2s$. This time window filters instantaneous spikes caused by electromagnetic interference (EMI), ensuring accuracy of fault determination.

• Specific Operating Conditions (Ignition Cycle) This monitoring logic is effective only when ignition switch is in ON position electrical activation state. When ignition switch is in OFF position, control unit power monitoring circuit enters sleep or low-power mode, at which time no fault frame recording and trigger determination is performed.

• Determination Conclusion Once satisfying logical conditions of "voltage greater than $16V$" and "duration exceeding 2s", occurring in "ON position" operating condition, Rear Domain Controller locks DTC C113017 fault code and illuminates fault indicator light on instrument panel.