Technical Explanation of C113116 Right Side Actuator Supply Undervoltage Fault

Fault Depth Definition

C113116 code identifies a specific electrical performance abnormality in the Electronic Parking Brake (EPB) system, specifically pointing to the right side actuator's power supply circuit voltage being lower than the controller's expected operating threshold. This fault code belongs to the chassis network diagnostic category within the whole vehicle domain control architecture. Its core logic involves real-time monitoring of the actuator-side power rail. When the control unit detects that the actual supplied voltage input to the rear right caliper motor cannot meet drive requirements, the system records an "under-voltage supply" status. This definition covers the entire feedback loop from power management to load response, aiming to ensure the reliability of the parking brake system when the vehicle is stationary. Diagnostic data indicates that this fault is directly related to the electronic parking controller's voltage monitoring module and the physical connectivity integrity of the right-side actuator circuit.

Common Fault Symptoms

Based on system feedback from C113116 original data, the following driving conditions or instrument panel phenomena may serve as intuitive representations of the fault:

• Right-side parking brake function is completely ineffective, unable to maintain vehicle stationary state.
• Dashboard displays Electronic Parking Brake warning light stays on or flashes.
• When attempting electronic parking locking operation, the actuating mechanism shows no response or sluggish action.
• Risk of vehicle rolling after stopping, especially under slope conditions.
• On-board Diagnostics System (OBD) records fault code and lights MIL (Engine Warning Light) area.

Core Fault Cause Analysis

According to original fault data, the technical source leading to this undervoltage fault is primarily attributed to hardware or logic abnormalities in the following three dimensions:

• Hardware Component (Actuator): Internal coil of the rear right caliper motor has risk of open circuit, or motor drive circuit suffers physical damage, causing load-side impedance change, resulting in voltage drop.
• Wiring/Connector (Physical Connection): Wiring harness between electronic parking control module and right side actuator shows high impedance contact, short-circuit to ground, or insulation damage; related connector terminals oxidize, back-pullout, or corrode leading to increased contact resistance, hindering current transmission.
• Controller (Logical Operation): Internal voltage monitoring circuit of electronic parking controller appears biased, unable to correctly identify normal load voltage drop, thus incorrectly determining insufficient supply, or power management module's voltage stabilization capability is abnormal.

Technical Monitoring & Trigger Logic

Control unit fault determination follows strict timing and condition logic. Specific monitoring mechanisms are as follows:

• Monitoring Target: System focuses on monitoring actual voltage value of right side actuator circuit and its stability relative to ground potential, simultaneously assessing current loop integrity.
• Numerical Range Condition: When detected supply voltage is lower than system set normal operating lower limit ($V_{supply} < V_{min}$) and duration exceeds preset threshold, fault logic is activated. Note: Specific thresholds are determined by manufacturer calibration software, specific model parameters need confirmation via standard repair manual.
• Trigger Condition Explanation: Fault determination is only valid within specific activation cycle. Must meet following pre-conditions: Start switch placed in ON position, and electronic parking switch pulled up or pressed. During vehicle stationary diagnostic enablement period, if above action accompanies voltage abnormality, system will immediately write C113116 fault code and store freeze frame data.