C113017 - C113017 Left Side Actuator Supply Over Voltage Fault

C113017 Left Actuator Supply Overvoltage Fault Technical Description

Fault Depth Definition

Fault code C113017 is identified as "Left Actuator Supply Overvoltage Fault," which belongs to the key diagnostic logic within the Electronic Parking Brake (EPB) control unit. In the vehicle electrical architecture, this fault code indicates that the control system has detected an abnormal increase in voltage on the power supply circuit connected to the left rear caliper motor. Specifically, the electronic parking control unit monitors the actual voltage level applied to the left actuator through its built-in analog input circuit in real time. When this value exceeds the system's preset safety threshold or reference baseline, it is judged as an overvoltage state. This fault definition covers the complete monitoring link from power management to the load end, involving the control unit's voltage sampling accuracy, line impedance changes, and external power system stability assessment. Its core lies in protecting the left rear caliper motor from high potential difference impact, preventing internal power device breakdown or mechanical structure damage due to power supply abnormalities.

Common Fault Symptoms

When the vehicle control system records C113017 code, vehicle owners and maintenance technicians can observe the following specific manifestations during driving:

• Left Rear Caliper Motor Function Failure: The affected left rear brake actuator cannot execute normal retract/extend stroke commands, which may result in the electronic handbrake being locked or unlocked incompletely.
• Instrument Panel Warning Light On: The Electronic Parking System warning indicator light (EPB Indicator) on the vehicle dashboard will stay illuminated, and may be accompanied by flashing, prompting the driver that there is communication or functional abnormality in the current braking system.
• Vehicle Driving Restrictions: In some vehicle models, this fault may cause the electronic parking brake function to be software-disabled, forcing a switch to mechanical emergency mode, or making it impossible to enable auto-hold functions.
• Charging Indicator Light Correlated Response: Due to potential fluctuations on the power side, other warning signals related to the power supply system may appear superimposed on the instrument display screen.

Core Fault Cause Analysis

Based on diagnostic data stream analysis, the causes of the C113017 fault can be classified into the following three technical dimensions, which require targeted troubleshooting based on vehicle electrical principles:

• Hardware Component Abnormality (Load End): Left Rear Caliper Motor Failure is the primary factor to consider. Voltage regulation modules or drive circuits inside the actuator may internally short, open, or have aging components, causing the control unit to mistakenly judge that the voltage on the power supply device side is too high; or motor winding insulation layer damage causes ground leakage, resulting in sampling voltage offset.
• Controller Logic Operation (Master End): Electronic Parking Controller Failure belongs to problems at the core control unit level. ADC calibration deviation inside the control unit, unstable reference voltage source, or internal monitoring program logic errors may all trigger false overvoltage alarm signals.
• External Power System (Input End): Abnormal status of the Charging System can cause vehicle voltage baseline fluctuations. When the on-board alternator output voltage is too high and exceeds the battery system stabilizing range, if the electronic parking brake system's ground return or filter capacitor performance decreases, high potential may be conducted along the actuator power supply line to the control unit sampling point, thereby satisfying the fault determination condition.

Technical Monitoring and Trigger Logic

The generation of this fault code follows rigorous electronic diagnostic strategies, with underlying logic including specific monitoring targets and environmental operating condition requirements:

• Monitoring Targets: The system collects voltage signal data connected to the left actuator in real time. Monitoring objects include ground potential difference for the power positive pole and dynamic voltage fluctuation amplitude of actuator drive pins.
• Trigger Fault Conditions: Diagnostics are active only when the Ignition Switch is placed in ON position. When ignition is off or power is disconnected, the control unit enters sleep mode, does not perform voltage sampling or comparison operations, and therefore will not record this fault code under these operating conditions.
• Judgment Logic Flow:
  1. When the ignition switch is turned on (ON position), the electronic parking control unit initializes its self-check program.
  2. The control unit enters dynamic monitoring mode, continuously reading voltage feedback values from the left actuator power supply circuit.
  3. If actual input voltage $V_{input}$ exceeds the system's internally preset overvoltage protection threshold (Over-voltage Threshold) and persists for a specific time window (e.g., several milliseconds to seconds).
  4. The system confirms that the signal is not instantaneous interference, finally locking into fault state and writing DTC C113017 in the data stream.
• Diagnostic Strategy Characteristics: This monitoring process belongs to the "Dynamic Function Test" category, meaning the overvoltage detection module is in high-sensitivity working state only when actuator power load is on or the system attempts to activate the actuator.