WOMS
P code powertrain Medium severity

P0579 Cruise Control Input Circuit Intermittent

The OBD2 code P0579 indicates an intermittent issue with the cruise control input circuit, which may affect the operation of the cruise control system

Definition

The OBD2 code P0579 indicates an intermittent issue with the cruise control input circuit, which may affect the operation of the cruise control system

Common causes

  • Faulty cruise control switch
  • Damaged wiring or connectors
  • Poor ground connection
  • Malfunctioning brake pedal switch
  • Faulty engine control module (ECM)
  • Intermittent electrical connections
  • Corroded terminals

Common misdiagnoses

  • Faulty brake switch
  • Malfunctioning cruise control module
  • Wiring issues or shorts in the circuit
  • Faulty accelerator pedal position sensor
  • Defective throttle position sensor
  • Issues with the engine control module (ECM)
  • Problems with the vehicle speed sensor (VSS)

Troubleshooting steps

  1. 1. Check for Additional Codes

    Before proceeding, check for any other related trouble codes that may provide more context to the problem

  2. 2. Inspect Wiring and Connectors

  3. 3. Visually inspect the wiring and connectors associated with the cruise control system. Look for signs of damage, corrosion, or loose connections

  4. 4. Pay special attention to the wiring harness leading to the cruise control switch and the brake pedal switch

  5. 5. Test the Cruise Control Switch

  6. 6. Use a multimeter to test the cruise control switch for proper operation. Ensure that it is sending the correct signals when engaged and disengaged

  7. 7. If the switch is faulty, it may need to be replaced

  8. 8. Check the Brake Pedal Switch

  9. 9. The brake pedal switch is crucial for the cruise control system. If it is malfunctioning, it can cause the cruise control to disengage or not function properly

  10. 10. Test the brake pedal switch to ensure it is working correctly. If it is faulty, replace it

  11. 11. Inspect the Cruise Control Module

  12. 12. If the wiring and switches are in good condition, the cruise control module itself may be faulty. Check for any signs of damage or corrosion

  13. 13. If possible, test the module with a scan tool to see if it is receiving and sending the correct signals

  14. 14. Check for Ground Issues

  15. 15. Ensure that all ground connections related to the cruise control system are secure and free of corrosion. Poor grounding can lead to intermittent issues

  16. 16. Look for Intermittent Issues

  17. 17. Since the code indicates an intermittent problem, try to replicate the issue by using the cruise control under different conditions (e.g., varying speeds, road conditions)

  18. 18. Pay attention to any patterns that may help identify the cause of the intermittent failure

  19. 19. Clear the Codes and Test Drive

  20. 20. After performing the checks and repairs, clear the trouble codes using an OBD-II scanner

  21. 21. Take the vehicle for a test drive to see if the code reappears. Monitor the cruise control operation during the drive

  22. 22. Consult a Professional

  23. 23. If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with cruise control systems and can perform more advanced diagnostics. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P0579 code