WOMS
P code powertrain Medium severity

P1855 Transmission Transfer Case Contact Plate 'C' Open Circuit

The OBD2 code P1855 indicates that there is an open circuit in the transmission transfer case contact plate 'C', which means that the electrical connection or signal from that specific contact plate is not functioning...

Definition

The OBD2 code P1855 indicates that there is an open circuit in the transmission transfer case contact plate 'C', which means that the electrical connection or signal from that specific contact plate is not functioning properly

Common causes

  • Faulty contact plate
  • Damaged wiring or connectors
  • Poor electrical connections
  • Short circuit in the wiring
  • Corroded terminals
  • Failed transfer case control module
  • Faulty transmission control module
  • Blown fuse related to the transfer case system

Common misdiagnoses

  • Faulty transfer case control module
  • Wiring issues or shorts in the harness
  • Defective transfer case motor
  • Malfunctioning transmission control module
  • Incorrectly diagnosed transmission issues
  • Faulty sensors related to the transfer case
  • Battery or electrical system problems
  • Issues with the vehicle's computer or software glitches

Troubleshooting steps

  1. 1. Check the Vehicle's Manual

    Refer to the vehicle's service manual for specific information related to the transfer case and the contact plate. This can provide insights into the wiring diagrams and component locations

  2. 2. Visual Inspection

  3. 3. Inspect the wiring harness and connectors associated with the transfer case contact plate. Look for any signs of damage, corrosion, or loose connections

  4. 4. Check for any frayed wires or broken connectors that could lead to an open circuit

  5. 5. Test the Contact Plate

  6. 6. If accessible, test the contact plate itself for continuity. Use a multimeter to check for resistance across the terminals. If there is no continuity, the contact plate may be faulty and require replacement

  7. 7. Check for Ground Issues

  8. 8. Ensure that the ground connections for the transfer case and contact plate are secure and free of corrosion. A poor ground can lead to open circuit conditions

  9. 9. Inspect the Transfer Case Control Module (TCCM)

  10. 10. If the vehicle is equipped with a TCCM, check for any fault codes stored in the module. Use a scan tool to read the codes and see if there are any related to the transfer case or contact plate

  11. 11. Inspect the TCCM for any signs of damage or water intrusion

  12. 12. Perform a Voltage Test

  13. 13. With the ignition on (engine off), use a multimeter to check for voltage at the contact plate connector. If there is no voltage present, trace the wiring back to the source to identify any breaks or shorts

  14. 14. Check for Other Codes

  15. 15. Look for any other related trouble codes that may provide additional context for the issue. Sometimes, multiple codes can point to a common problem

  16. 16. Clear Codes and Test Drive

  17. 17. After performing repairs or adjustments, clear the trouble codes using a scan tool and take the vehicle for a test drive to see if the code returns

  18. 18. Consult a Professional

  19. 19. If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or technician who has experience with your specific vehicle make and model. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P1855 code