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P1851 Transmission Transfer Case Contact Plate 'B' Open Circuit

The OBD2 code P1851 indicates that there is an open circuit in the transmission transfer case contact plate 'B', which means that the electrical connection or signal from that component is not functioning properly

Definition

The OBD2 code P1851 indicates that there is an open circuit in the transmission transfer case contact plate 'B', which means that the electrical connection or signal from that component is not functioning properly

Common causes

  • Faulty contact plate
  • Damaged wiring or connectors
  • Poor electrical connections
  • Short circuit in the wiring
  • Failed transfer case control module
  • Corrosion or dirt in connectors
  • Faulty transmission control module

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 for Additional Codes

    Use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are multiple issues

  2. 2. Inspect Wiring and Connectors

    Visually inspect the wiring harness and connectors associated with the transfer case contact plate. Look for

  3. 3. Damaged, frayed, or corroded wires

  4. 4. Loose or disconnected connectors

  5. 5. Signs of moisture or dirt that could affect connections

  6. 6. Test the Contact Plate

    If accessible, test the contact plate itself for continuity. Use a multimeter to check for an open circuit. If the contact plate is faulty, it may need to be replaced

  7. 7. Check Power and Ground

    Verify that the contact plate is receiving the proper voltage and ground. Use a multimeter to check for power at the connector when the ignition is on

  8. 8. Ensure that the ground connection is solid and free of corrosion

  9. 9. Inspect the Transfer Case Control Module

    Check the transfer case control module for any signs of damage or corrosion. If the module is faulty, it may need to be replaced or reprogrammed

  10. 10. Look for Mechanical Issues

    Inspect the transfer case for any mechanical issues that could affect the operation of the contact plate. Ensure that the transfer case is functioning properly and that there are no obstructions

  11. 11. Clear Codes and Test Drive

    After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner. Take the vehicle for a test drive to see if the code returns

  12. 12. Seek Professional Help

    If the issue persists after performing these 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 P1851 code