WOMS
P code powertrain Medium severity

P1807 Transmission 4-Wheel Drive High Indicator Short Circuit To Ground

The OBD2 code P1807 indicates a short circuit to ground in the transmission's 4-wheel drive high indicator circuit, which may cause the indicator light to malfunction or not function at all

Definition

The OBD2 code P1807 indicates a short circuit to ground in the transmission's 4-wheel drive high indicator circuit, which may cause the indicator light to malfunction or not function at all

Common causes

  • Damaged wiring or connectors
  • Faulty 4WD switch
  • Short circuit in the wiring harness
  • Malfunctioning transfer case control module
  • Corroded connectors
  • Faulty indicator light or bulb
  • Grounding issues in the electrical system

Common misdiagnoses

  • Faulty transfer case switch
  • Wiring harness issues
  • Shorted or damaged wiring
  • Faulty transmission control module (TCM)
  • Incorrectly installed or malfunctioning 4WD actuator
  • Faulty dashboard indicator light
  • Issues with the vehicle's body control module (BCM)
  • Problems with the transfer case itself

Troubleshooting steps

  1. 1. Check the Vehicle's Manual

    Refer to the vehicle's service manual for specific information about the 4WD system and wiring diagrams

  2. 2. Visual Inspection

    Inspect the wiring and connectors related to the 4WD high indicator circuit. Look for

  3. 3. Damaged, frayed, or corroded wires

  4. 4. Loose or disconnected connectors

  5. 5. Signs of moisture or dirt in connectors

  6. 6. Check the 4WD Switch

    Test the 4WD switch (if applicable) for proper operation. Ensure it is functioning correctly and not stuck in the "on" position

  7. 7. Use a multimeter to check for continuity and proper voltage at the switch

  8. 8. Inspect the Indicator Light

    Check the 4WD high indicator light on the dashboard. Ensure it is not shorted to ground

  9. 9. If the light is malfunctioning, it may cause the code to trigger

  10. 10. Test for Short Circuits

    Use a multimeter to check for continuity between the 4WD high indicator circuit and ground. If there is continuity, it indicates a short circuit

  11. 11. Trace the wiring harness to locate the source of the short

  12. 12. Check the Transfer Case Control Module (if applicable)

    If your vehicle has a transfer case control module, check for proper operation and any stored trouble codes

  13. 13. Inspect the module for damage or corrosion

  14. 14. Clear the Code and Test Drive

    After performing repairs, clear the trouble code using an OBD-II scanner

  15. 15. Take the vehicle for a test drive to see if the code returns

  16. 16. Consult a Professional

    If the issue persists after performing the above steps, consider consulting a professional mechanic or technician who specializes in your vehicle's make and model.Additional Tips: - Always disconnect the battery before working on electrical components to avoid shorts or shocks. - Document any changes or repairs made during the troubleshooting process for future reference. By following these steps, you should be able to identify and resolve the issue related to the P1807 code