C1163

What Does Code C1163 Mean?

DTC C1163 indicates a detected electrical fault in the circuit associated with the Park Brake Switch #2, specifically reporting a short to ground condition. In modern automotive systems, the parking brake status is a critical input for various control modules, including the Anti-lock Braking System (ABS), Electronic Stability Program (ESP), Traction Control System (TCS), Transmission Control Module (TCM), and sometimes even the Engine Control Module (ECM) or a dedicated Electronic Parking Brake (EPB) control unit. The “Switch #2” designation typically implies either a redundant switch for safety and verification purposes, a switch for a secondary or auxiliary parking brake function, or a specific input within a more complex parking brake system (e.g., separate switch for EPB motor engagement versus pedal/lever position sensing).

The control module responsible for monitoring this circuit (often the ABS/ESP module or BCM) expects to see a specific voltage range on the signal wire when the park brake switch is in its released (open) state, typically a pull-up voltage provided by the module itself (e.g., 5V or battery voltage through a resistor). When the switch is applied (closed), it normally provides a path to ground, causing the voltage on the signal line to drop near 0V. Code C1163 is set when the module detects a persistent low voltage (near 0V) on the Park Brake Switch #2 circuit, indicating a constant short to ground, even when the actual parking brake mechanism is in the released position. This leads the module to incorrectly believe the parking brake is continuously engaged, which can impact vehicle dynamics, safety features, and driver assistance systems.

Common Symptoms

• Illuminated Parking Brake Warning Light: The most direct symptom, indicating the system perceives the parking brake as engaged.
• ABS/ESP/Traction Control Warning Lights: These systems often rely on parking brake status and may deactivate or illuminate a warning if the input is erroneous.
• Brake System Warning Light: A general brake system fault indicator may appear.
• Electronic Parking Brake (EPB) Malfunction: If applicable, the EPB may fail to engage or disengage, or behave erratically.
• Cruise Control Deactivation: Cruise control systems typically disengage if the parking brake is sensed as applied.
• Transmission Shift Interlocks: In some vehicles, shifting out of Park (P) may be inhibited if the module erroneously detects the parking brake engaged.
• Reduced Engine Power or Limp Mode: Less common, but some systems might enter a restricted operating mode to prevent driving with a perceived engaged parking brake.

What Causes the Code C1163?

• Faulty Park Brake Switch #2: An internal electrical short-circuit to ground within the switch itself, causing it to constantly send an “applied” signal regardless of the actual parking brake position.
• Wiring Harness Damage:
  • A short to ground in the signal wire between the park brake switch #2 and the respective control module. This can be due to chafed insulation, pinched wires, or heat damage.
  • Corrosion or damage within the wiring harness leading to unintended ground paths.
• Connector Issues:
  • Corroded, bent, or loose pins within the electrical connector at the park brake switch #2 or at the control module (e.g., ABS/ESP module, BCM, EPB module).
  • Water intrusion into the connector causing a short to ground.
• Control Module Malfunction: While less common, an internal fault within the monitoring control module (e.g., ABS/ESP module, BCM, EPB module) can cause it to misinterpret the signal or generate an internal short, leading to a false C1163 code.

How to Diagnose and Troubleshoot

Diagnosing C1163 requires a systematic approach, often involving a professional scan tool and a digital multimeter (DMM).

1. Initial Visual Inspection: Begin by visually inspecting the parking brake switch #2 (if accessible), its wiring harness, and connectors for any obvious signs of damage, chafing, corrosion, or improper installation. Pay close attention to areas where wiring passes through firewalls, along chassis rails, or near moving parts.
2. Scan Tool Data Analysis:
   • Connect an OBD-II scanner capable of reading live data from relevant control modules (ABS/ESP, BCM).
   • Monitor the “Park Brake Switch #2 Status” or similar Parameter ID (PID). Observe if it consistently reads “Applied,” “On,” or “Closed” regardless of the physical position of the parking brake lever/pedal. This confirms the module is receiving a short-to-ground signal.
   • Check for any other related DTCs that might provide additional context.
3. Digital Multimeter (DMM) Testing at the Switch:
   • Isolate the Switch: Disconnect the electrical connector from Park Brake Switch #2.
   • Power and Ground Check (Harness Side): Using the DMM, check for proper power supply (if applicable) and ground at the harness side of the connector according to the vehicle’s wiring diagram. The signal wire (module input) should typically show a pull-up voltage (e.g., 5V or 12V) when disconnected from the switch. If it reads near 0V, there’s a short to ground in the harness between the connector and the control module.
   • Switch Continuity/Resistance Test (Switch Side): With the connector disconnected, use the DMM to test the switch itself.
     • If it’s a normally open switch that closes to ground when applied: In the released position, there should be infinite resistance (open circuit) between the signal pin and ground. In the applied position, there should be very low resistance (near 0 ohms). If it shows low resistance in the released position, the switch is internally shorted.
     • Refer to the vehicle-specific service manual for the exact switch type and expected values.
4. Wiring Harness Integrity Test:
   • If the signal wire on the harness side showed a short to ground in step 3, or if the switch tested good, proceed to test the wiring.
   • Disconnect the connector at Park Brake Switch #2 AND the corresponding control module connector (e.g., ABS/ESP module).
   • Using the DMM, perform a continuity test between the signal wire pin at the switch connector and the corresponding pin at the control module connector. It should show very low resistance (near 0 ohms).
   • Perform a resistance test from the signal wire pin to a known good chassis ground. There should be infinite resistance (open circuit). If a low resistance value is detected, there is a short to ground within the wiring harness. Carefully trace the wire path to locate the short.
5. Control Module Verification: If all wiring, connectors, and the switch itself test perfectly, and the DTC persists, the issue might lie within the control module itself. This is a less common failure but can occur due to internal component failure. Requires specialized diagnostic tools and expertise to confirm.

Recommended Repairs and Solutions

• Replace Faulty Park Brake Switch #2: If DMM tests confirm an internal short within the switch, replace it with a new OEM or equivalent quality part. Ensure proper adjustment if it’s a mechanically activated switch.
• Repair or Replace Damaged Wiring Harness: If a short to ground is identified in the wiring, locate the precise point of damage. Repair the damaged section using appropriate automotive-grade wiring repair techniques (e.g., soldering and heat-shrink tubing) or replace the entire affected harness segment if the damage is extensive.
• Clean or Repair Corroded Connectors: If corrosion or poor pin tension is found in the connectors, clean the terminals thoroughly using electrical contact cleaner and a small brush. If pins are bent, broken, or severely corroded, replace the affected terminals or the entire connector. Ensure a tight, weather-sealed connection.
• Replace Control Module: If extensive diagnosis confirms the control module (e.g., ABS/ESP, BCM, EPB module) is at fault and all external circuits are verified as good, the module will require replacement. This often involves specific programming or coding procedures with a factory-level scan tool after installation.
• Clear DTCs and Test Drive: After performing any repairs, clear the C1163 DTC and any related codes using an OBD-II scanner. Conduct a thorough test drive to ensure the repair is successful and the code does not return. Monitor live data for the park brake switch status during the test drive.