C117007 - C117007 EPB Switch Stuck

Fault Depth Definition

C117007 is a specific fault code within the Electronic Parking Brake (EPB) system, specifically referring to "EPB Switch Stuck". Within the vehicle electronic control architecture, this code identifies anomalies in the signal transmission or logical status of the electronic parking switch. From the perspective of the Control Unit, this fault reflects that the system input signal cannot be converted according to the expected timing sequence, typically manifesting as the switch state being locked at a non-normal logical level, causing the controller to fail to correctly identify the driver's operational intent. This definition emphasizes the system's requirement for signal integrity in real-time feedback, ensuring that the execution logic of the electronic parking system remains consistent with the physical input instructions of the driver, preventing risks of braking malfunction or failure caused by signal sticking.

Common Fault Symptoms

When the electronic parking switch signals stickiness, the Control Unit writes the abnormal status to memory and activates corresponding indicator lights. Owners and repair technicians can observe specific system feedback as follows:

• Dashboard Warning Light Illuminated: The "Parking Brake" warning light (handbrake icon) on the vehicle dashboard will illuminate continuously or flicker for a long time, indicating the braking system is in a non-normal state.
• No Response to Braking Command: When attempting to release or apply electronic parking brake operation during driving, the system may be completely unable to execute corresponding motor actions or logic control.
• System Limit Mode Triggered: To protect chassis and braking mechanisms safety, the vehicle may enter a fault running mode, causing the electronic parking function to become temporarily unavailable, while prohibiting gear shifting after P-gear unlocking.
• DTC Storage Record: The vehicle's On-Board Diagnostics (OBD) system will retain freeze frame data for this fault code for subsequent technical analysis.

Core Fault Cause Analysis

According to the Control Unit's diagnostic logic, the occurrence of C117007 is primarily triggered by hardware or software anomalies in the following three dimensions:

• Hardware Component Anomaly Refers to physical degradation of the mechanical structure or electrical characteristics of the electronic parking switch itself. This includes internal contact oxidation, mechanical return spring failure preventing the lever from resetting, or Hall Sensor (Hall Sensor) sensing element damage, resulting in the switch being unable to generate correct electrical signal changes after physical pressing.

• Line or Connector Failure Covers the physical link integrity between the electronic parking switch and the Control Unit. Includes wiring internal breaks, excessive contact resistance, loose soldering at pins, or signal voltage anomalies caused by external electromagnetic interference (such as short circuit to ground or power supply). Such issues cause the level value received by the Control Unit when reading the switch status to deviate from normal operating thresholds.

• Controller Logic Operation Fault The Electronic Parking Brake System Control Unit itself has logic processing errors. When input signals exceed preset voltage ranges or rate of change does not match algorithm expectations, the controller's internal logic may determine a "stuck" state and trigger counter recording mechanisms. Additionally, program checksum errors or memory data loss can also lead to misjudgment of normal signals.

Technical Monitoring and Trigger Logic

The Control Unit's determination of this fault code follows a strict real-time monitoring process, with its trigger logic based on the following specific conditions:

• Monitored Target Parameters The system continuously monitors the signal voltage status and duty cycle changes of the electronic parking switch to verify if the signal is stable and switches within allowed conversion intervals. The controller maintains an Electronic Parking Switch Fault Counter Readout Record, when the number of occurrences or duration of abnormal events within a single cycle reaches the set threshold, the fault code will be activated and the warning light illuminated.

• Triggered Fault Conditions This monitoring process is conducted only in specific vehicle power states. Placing the Ignition Switch in ON position is the prerequisite for triggering fault logic determination. Once the ignition system is enabled, the Control Unit enters self-check and real-time diagnostic mode. If it detects that the switch signal has not changed as expected or is at a fixed level (not dynamic jumping), and the duration exceeds the calibrated value, the system will immediately record DTC C117007. This logic ensures that input signal validity verification only occurs when the vehicle is ready for operation and driver intent is clear.