P0567

What Does Code P0567 Mean?

DTC P0567 signifies a detected malfunction in the cruise control system’s resume signal circuit. The Powertrain Control Module (PCM), or Engine Control Module (ECM) in some architectures, is responsible for monitoring the electrical integrity and operational state of the various cruise control input switches. Specifically, for P0567, the PCM has detected an input signal from the cruise control “RESUME” switch that is either outside of its expected voltage range or is inconsistent with its programmed operational parameters. This typically means the PCM is not receiving the correct voltage drop or change that corresponds to the resume switch being pressed, or it is detecting a signal when the switch is not activated, indicating an electrical anomaly within the circuit. The cruise control system, a critical subsystem for driver convenience and fuel economy during highway operation, relies on precise electrical signals from each switch to govern vehicle speed. A fault in the resume signal directly impacts the PCM’s ability to reactivate a previously set cruise speed, often rendering the entire cruise control system inoperative or causing intermittent functionality.

Common Symptoms

• Inoperative Cruise Control System: The most immediate and common symptom, where the cruise control cannot be engaged at all, or will not resume speed.
• Resume Function Failure: While other cruise control functions (SET, ON/OFF) may appear to work, the “RESUME” button specifically fails to reactivate the last set speed.
• Malfunction Indicator Lamp (MIL) Illumination: The “Check Engine” light may illuminate, indicating a detected fault within the powertrain system.
• Intermittent Cruise Control Operation: The system may occasionally work, then fail, suggesting a loose connection or an intermittently failing switch.

What Causes the Code P0567?

• Faulty Cruise Control Resume Switch: The most common cause, where the internal contacts of the switch become worn, corroded, or damaged, preventing it from sending the correct signal.
• Damaged Wiring Harness: Open circuits, short circuits to ground or voltage, or high resistance within the wiring connecting the resume switch to the PCM. This can be due to chafing, rodent damage, or pinched wires.
• Corroded or Loose Electrical Connectors: Oxidation or poor pin tension at the cruise control switch connector or the PCM connector can disrupt the signal integrity.
• Faulty Clock Spring (Spiral Cable): If the cruise control switches are mounted on the steering wheel, a damaged clock spring can interrupt electrical continuity to the switches.
• Powertrain Control Module (PCM) Malfunction: While less common, an internal fault within the PCM preventing it from correctly interpreting the resume switch input can cause this code.

How to Diagnose and Troubleshoot

Diagnosis of P0567 requires a methodical approach, utilizing an OBD-II scanner, a Digital Multimeter (DMM), and comprehensive wiring diagrams specific to the vehicle.

1. Retrieve and Document Freeze Frame Data: Use an OBD-II scanner to retrieve DTC P0567 and any associated freeze frame data. This data provides a snapshot of operating conditions when the code was set, which can be useful for replication. Clear the code after documentation.
2. Visual Inspection:
   • Inspect the cruise control resume switch for any physical damage, misalignment, or debris that might impede its operation.
   • Carefully trace the wiring harness from the cruise control switches to the PCM, looking for signs of chafing, pinching, corrosion, or rodent damage. Pay close attention to areas where the harness passes through firewalls or near moving components.
   • Check all relevant electrical connectors for corrosion, bent pins, or loose connections. Disconnect, inspect, and reconnect where appropriate, ensuring proper dielectric grease application if necessary.
3. Verify Switch Operation via Scan Tool Live Data: If the vehicle’s PCM supports it, access live data streams for the cruise control switches. Observe the “RESUME” switch status while pressing and releasing the switch. The status should change consistently (e.g., from “OFF” to “ON” or a voltage change). If no change occurs, or if it shows a constant “ON” or “OFF” state regardless of switch activation, the circuit is suspect.
4. Electrical Circuit Testing with DMM:
   • Power and Ground Verification: With the ignition ON, verify the presence of reference voltage (typically 5V or 12V) at the cruise control switch connector using a DMM. Also, check for a good ground connection at the switch assembly (if applicable).
   • Resume Switch Continuity/Resistance Test: Disconnect the resume switch from the harness. Using the DMM in continuity or resistance mode, test the switch itself. When pressed, the switch should either show continuity (0 ohms) or a specific resistance value (if part of a resistor ladder network, common for multiplexed switches). When released, it should show infinite resistance or a different specified resistance. Consult the vehicle’s service manual for exact resistance specifications.
   • Wiring Integrity Test (Open/Short): With the switch disconnected and the PCM connector removed (consult wiring diagrams for specific pinouts), use the DMM to check for continuity between the resume switch signal wire at the switch connector and its corresponding pin at the PCM connector. There should be very low resistance (typically < 5 ohms). Also, check for shorts to ground and shorts to voltage on the signal wire.
5. Clock Spring Inspection (if applicable): If the switches are steering wheel mounted, and continuity tests fail for the wiring, the clock spring could be faulty. Testing the clock spring involves checking continuity through its windings as the steering wheel is rotated.

Recommended Repairs and Solutions

Based on the diagnostic findings, the following repairs are commonly recommended:

1. Replace the Cruise Control Resume Switch: If DMM tests confirm the resume switch itself is faulty (e.g., no change in resistance, open circuit, or short circuit when activated), replacing the switch assembly is the most direct solution. Ensure the replacement part is OEM quality or a reputable aftermarket equivalent.
2. Repair or Replace Damaged Wiring: If the visual inspection or continuity tests revealed an open circuit, short circuit, or high resistance in the wiring harness, repair the affected section using proper soldering techniques and heat shrink tubing, or replace the entire harness segment if damage is extensive.
3. Clean or Replace Corroded Connectors: For corroded or loose connectors, use electrical contact cleaner and a small brush to clean the terminals. If pins are bent or severely corroded, the connector shell and pins may need to be replaced. Ensure secure connections.
4. Replace the Clock Spring: If diagnostics point to a faulty clock spring, replacement is necessary. This often involves removing the steering wheel and airbag (exercise extreme caution and follow manufacturer safety procedures for airbag systems).
5. PCM Replacement (Last Resort): If all other components and wiring have been thoroughly tested and confirmed to be functioning correctly, and the PCM is demonstrably not interpreting the correct input signal, PCM replacement or reprogramming may be necessary. This is a rare occurrence for P0567 and should only be pursued after exhausting all other diagnostic avenues.

Mechanics’ Tip: After any repair, always clear the DTCs from the PCM memory using an OBD-II scanner. Then, perform a comprehensive test drive, actively engaging and disengaging the cruise control, and specifically testing the “RESUME” function multiple times to confirm the repair is successful and the code does not return.