C1164

What Does Code C1164 Mean?

DTC C1164 signifies a circuit malfunction within the Park Brake Actuator Assembly Switch. This code is typically set by the vehicle’s Electronic Brake Control Module (EBCM) or a dedicated Parking Brake Control Module (PBCM), which then communicates this fault to the Powertrain Control Module (PCM) or Engine Control Module (ECM) via the Controller Area Network (CAN) bus. The control module monitors the electrical signal from a position switch integrated within or associated with the park brake actuator assembly. This switch provides critical feedback regarding the current state of the parking brake system, specifically whether it is engaged, disengaged, or potentially at an intermediate position depending on system design. When the control module detects an implausible signal—such as an open circuit, a short to ground, a short to voltage, an incorrect voltage range, or a signal that fails to transition correctly with actuator movement—it interprets this as a circuit failure and stores code C1164. This indicates that the electrical integrity of the feedback circuit from the park brake actuator switch is compromised, preventing the module from accurately determining or verifying the park brake’s operational status.

Common Symptoms

• Parking Brake Warning Light Illumination: The primary and most common symptom is the activation of the parking brake warning light on the instrument cluster, often accompanied by a “Service Park Brake” or similar message.
• Inoperative Parking Brake: The Electronic Parking Brake (EPB) system may fail to engage or disengage when commanded, rendering the feature unusable.
• Intermittent Parking Brake Operation: The EPB might work intermittently, sometimes engaging or disengaging, and other times failing to respond.
• Reduced or Restricted Vehicle Operation: Some vehicle systems may enter a ‘limp home’ mode or restrict certain functions if a critical safety system like the parking brake is deemed faulty.

What Causes the Code C1164?

• Faulty Park Brake Actuator Switch: The electrical contacts within the position switch, which is either standalone or integrated into the actuator assembly, may be worn, corroded, or physically damaged, leading to an incorrect or absent signal.
• Damaged Wiring Harness: The electrical wiring connecting the park brake actuator switch to its control module can suffer from open circuits (broken wires), short circuits to ground or power, chafed insulation, or internal corrosion within the wire strands.
• Corroded or Loose Electrical Connectors: Corrosion within the multi-pin connectors at the park brake actuator assembly or the control module can impede proper signal transmission. Loose pins or improperly seated connectors can also cause intermittent or complete signal loss.
• Faulty Park Brake Actuator Assembly: In many modern systems, the position switch is an integral part of the electric park brake actuator (often integrated into the caliper). A mechanical failure within the actuator (e.g., seized motor, stripped gears) can prevent the switch from changing state correctly, or the internal switch itself could fail as part of the assembly.
• Parking Brake Control Module (PBCM/EBCM) Failure: Although less common, an internal fault within the control module responsible for reading the switch input could lead to misinterpretation of the signal or a failure to supply necessary reference voltage or ground.

How to Diagnose and Troubleshoot

Diagnosing C1164 requires a systematic approach using specialized tools and a thorough understanding of electrical circuits.

1. Retrieve All DTCs and Freeze Frame Data: Use a capable OBD-II diagnostic scanner to confirm C1164. Crucially, check for any related C-codes, B-codes (body), U-codes (network communication), or even P-codes that might provide additional context to the failure. Analyze freeze frame data to understand the operating conditions (e.g., vehicle speed, system voltage) when the code was set.
2. Visual Inspection of the EPB System:
   • Inspect the park brake actuator assembly, its motor, and all visible wiring for signs of physical damage, corrosion, rodent damage, or chafing. Pay close attention to the wiring harness where it passes through chassis components or is exposed to road debris.
   • Carefully inspect all electrical connectors associated with the actuator and its control module. Look for bent or corroded pins, signs of water ingress, or improper seating. Clean any visible corrosion with electrical contact cleaner.
3. Verify Power and Ground to the Actuator and Switch Circuit:
   • Using a vehicle-specific wiring diagram, identify the power supply and ground circuits for the park brake actuator and its associated switch.
   • With the ignition ON (and the vehicle in PARK, brake applied), use a Digital Multimeter (DMM) to check for the correct voltage (typically battery voltage or a 5V reference) at the actuator and switch connector(s).
   • Verify good ground integrity by checking for continuity to chassis ground with the DMM (or voltage drop testing under load).
4. Perform Wiring Integrity Checks (Continuity and Short Tests):
   • Disconnect the battery to prevent accidental shorting or damage to control modules.
   • Isolate the park brake actuator switch circuit by disconnecting its connectors from both the actuator/switch and the control module.
   • Using the DMM, perform continuity tests on each wire in the circuit between the switch connector and the control module connector. An “OL” or high resistance reading indicates an open circuit.
   • Perform short-to-ground tests by checking for continuity between each wire and chassis ground. Any continuity indicates a short.
   • Perform short-to-power tests (if safe to do so with battery connected and ignition on, otherwise visually inspect).
5. Test the Park Brake Actuator Switch:
   • If the switch is a separate component and accessible, use the DMM to test its resistance or continuity in both its “engaged” and “disengaged” states (as per service manual specifications). Look for a consistent change in reading.
   • If the switch is integrated into the actuator, a specific functional test or resistance value may be listed in the service manual.
6. Actuator Functionality Test (Bidirectional Scan Tool):
   • If available, use a diagnostic scanner with bidirectional control capabilities to command the park brake actuator to engage and disengage.
   • Observe if the actuator mechanically operates. Simultaneously, monitor the live data stream for the park brake switch status. If the actuator moves but the switch status doesn’t change, the internal switch or its feedback mechanism is likely faulty. If the actuator doesn’t move, investigate power/ground to the actuator motor.
7. Control Module Self-Test and Configuration: If all wiring and components test good, and a known good actuator assembly (if applicable) does not resolve the issue, the control module itself (PBCM/EBCM) might be faulty. Perform a self-test of the module via the scan tool if available.

Recommended Repairs and Solutions

The repair strategy for C1164 depends directly on the root cause identified during diagnosis.

• Repair or Replace Damaged Wiring: If the diagnostic process reveals an open circuit, short, or corroded wiring, the affected section of the wiring harness must be repaired or replaced. Use proper automotive-grade wiring repair techniques, including soldering and heat-shrinking, or use factory-specified crimp and splice connectors. Ensure any repaired section is adequately protected from future damage and moisture.
• Clean or Replace Corroded Connectors: For corroded connectors, use electrical contact cleaner to meticulously clean the pins. If corrosion is severe or pins are damaged, the connector housing and pins should be replaced. Apply dielectric grease to protect against future corrosion.
• Replace Faulty Park Brake Actuator Switch: If the park brake position switch is a separate, replaceable component and tests confirm its failure, replace it with an OEM-equivalent part.
• Replace Park Brake Actuator Assembly: In many contemporary vehicles, the position switch is integrated within the electric parking brake actuator, which may be part of the caliper assembly. If the switch is internal, or if the actuator motor itself is faulty and prevents proper switch operation, the entire park brake actuator assembly will need replacement. Always consult the service manual for specific procedures, as some EPB systems require a special “service mode” to retract the caliper before replacement to prevent damage.
• Replace Parking Brake Control Module (PBCM/EBCM): If all other components (wiring, switch, actuator) have been thoroughly tested and confirmed to be functioning correctly, and the control module is suspected, replacement may be necessary. Be aware that control module replacement often requires programming or coding to the vehicle using a specialized scan tool to ensure proper communication and function.
• Clear DTCs and Perform System Initialization: After any repair, clear the C1164 and any other related DTCs using an OBD-II scanner. Many EPB systems require a specific initialization or calibration procedure after component replacement (e.g., actuator, module) to ensure proper operation and clear system warnings. Follow the vehicle manufacturer’s specified procedure in the service manual.
• Mechanics’ Tip: Always consult the vehicle’s specific service information for detailed wiring diagrams, component locations, test specifications, and replacement procedures. EPB systems vary significantly between manufacturers, and specific torque values, calibration steps, and safety warnings (e.g., disabling the system before working on it) are crucial for a successful repair.