C113016 - C113016 Left Actuator Power Supply Undervoltage Fault

Fault Depth Definition

C113016 Left Actuator Supply Undervoltage Fault, is a specific diagnostic trouble code triggered by internal diagnostic logic within the Electronic Parking Brake (EPB) system. This code explicitly indicates that during vehicle operation, the control unit detects power supply voltage allocated to the left parking brake actuator falling below the system preset operating threshold. As a safety-critical subsystem for the entire vehicle, this fault is directly related to the electrical integrity of the parking mechanism. Within the hardware architecture of the system, this monitoring is typically implemented by the Rear Domain Controller or a dedicated EPB Electronic Control Unit, whose core function is to evaluate the physical state of the power supply path, ensuring that when actuator action commands are issued, the left motor receives stable and sufficient electrical energy input. The generation of this fault code means there is an abnormality in the voltage regulation or transmission link within the power supply circuit, unable to maintain normal logic operation and physical drive of the actuator.

Common Fault Symptoms

When the diagnostic system determines C113016 is valid and enters the fault storage state, drivers usually perceive the following specific vehicle behaviors:

• Left Brake Function Failure: Under static parking conditions, the left actuator cannot provide the necessary locking torque, causing the electronic handbrake to lose the ability to hold the vehicle parking position at a physical level.
• Abnormal Operation Feedback: When attempting brake release or locking operations via the EPB switch, the system fails to complete a complete action loop, which may cause the control unit to refuse execution of instructions or record verification failure.
• Diagnostic Logic Blockage: During internal vehicle self-check procedures, if this fault condition is triggered, it interrupts the function verification process for the left parking brake, failing to meet the system predetermined verification standards.

Core Fault Cause Analysis

Root cause analysis for C113016 fault code mainly covers hardware or logic anomalies in the following three dimensions:

• Fuse Blown: The key protective component responsible for powering the left actuator (such as a specific numbered FUSE) undergoes physical fusion. This is usually caused by circuit overcurrent protection action, aging breakdown, or external short circuits, directly cutting off the power supply path to the load end.
• Wiring or Connector Fault: Power lines connecting the left actuator have open circuit risks, or electrical connectors appear loose, pins corroded, contact resistance too high, etc. These factors will cause voltage drop during current transmission, making the actual voltage reaching the actuator end lower than the minimum working requirement value.
• Rear Domain Controller Fault: As a core control unit for signal processing and power distribution, its rear domain controller may have internal voltage monitoring circuit drift or degraded drive output module performance. If the controller's internal logic cannot correctly maintain the working voltage required by the actuator, even with good external wiring, this undervoltage fault record will still be triggered.

Technical Monitoring and Trigger Logic

System fault determination relies on specific dynamic condition monitoring processes, with the specific logic structure as follows:

• Trigger Pre-conditions: The diagnostic procedure is only activated when "the start switch is placed in ON position". This ensures that the vehicle's master power is connected and the control unit is in a ready-to-work state.
• Actuation Input Signal: Under system monitoring, "EPB switch operation" must be performed, meaning the driver or diagnostic equipment attempts to send locking or unlocking commands to the left actuator to activate the motor drive circuit.
• Monitoring Target and Judgment Standard: In the real-time feedback loop of the Rear Domain Controller, the focus is on verifying the stability and magnitude of voltage signals. When the system enters the "left parking brake verification failed during check" state, if power supply voltage at the left actuator input is detected to continuously fall below the allowed operating range (i.e., supply undervoltage), the control unit will immediately flag fault code C113016 and prohibit relevant function execution. This logic aims to precisely distinguish motor faults from power supply faults, ensuring correct triggering of safety strategies.