WOMS
P code powertrain Medium severity

P1806 Transmission 4-Wheel Drive High Indicator Short Circuit To Battery

The OBD2 code P1806 indicates a short circuit in the transmission's 4-wheel drive high indicator circuit, which is causing it to receive a constant signal from the battery, potentially leading to incorrect operation of...

Definition

The OBD2 code P1806 indicates a short circuit in the transmission's 4-wheel drive high indicator circuit, which is causing it to receive a constant signal from the battery, potentially leading to incorrect operation of the 4WD system

Common causes

  • Shorted wiring or connectors
  • Faulty 4WD high indicator switch
  • Malfunctioning transfer case control module
  • Corroded or damaged electrical connections
  • Faulty instrument cluster
  • Issues with the body control module (BCM)

Common misdiagnoses

  • Faulty transfer case switch
  • Wiring harness issues
  • Faulty transmission control module (TCM)
  • Defective 4WD actuator
  • Malfunctioning dashboard indicator light
  • Battery or charging system problems
  • Incorrectly diagnosed transmission issues
  • Grounding problems in the electrical system

Troubleshooting steps

  1. 1. Check the Vehicle's Manual

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

  2. 2. Visual Inspection

    Inspect the wiring and connectors related to the 4WD system, particularly those associated with the high indicator circuit. Look for

  3. 3. Damaged or frayed wires

  4. 4. Corroded or loose connectors

  5. 5. Signs of wear or exposure to heat or moisture

  6. 6. Check the 4WD Switch

    Test the 4WD switch (if applicable) for proper operation. Ensure that it is functioning correctly and that there are no shorts in the switch itself

  7. 7. Inspect the Indicator Light

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

  8. 8. Test for Short Circuits

    Use a multimeter to check for continuity in the wiring harness. Look for any shorts to ground or battery voltage in the circuit

  9. 9. Disconnect the battery and test the circuit for continuity with the switch in different positions

  10. 10. Check the Control Module

    If the wiring and switch are in good condition, the issue may lie within the control module for the 4WD system. Check for any fault codes in the module and inspect for proper operation

  11. 11. Inspect Ground Connections

    Ensure that all ground connections related to the 4WD system are clean and secure. Poor ground connections can lead to erratic behavior and false codes

  12. 12. Clear the Code

    After performing the checks and repairs, clear the code using an OBD-II scanner and take the vehicle for a test drive to see if the code returns

  13. 13. Consult a Professional

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with the specific make and model of your vehicle.Additional Tips: - Always ensure safety by disconnecting the battery before working on electrical components. - 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 P1806 code