WOMS
P code powertrain Medium severity

P1805 Transmission 4-Wheel Drive High Indicator Open Circuit

The OBD2 code P1805 indicates that there is an open circuit in the transmission's 4-wheel drive high indicator circuit, meaning the system is not receiving the expected signal that the 4WD high mode is engaged

Definition

The OBD2 code P1805 indicates that there is an open circuit in the transmission's 4-wheel drive high indicator circuit, meaning the system is not receiving the expected signal that the 4WD high mode is engaged

Common causes

  • Faulty 4WD indicator switch
  • Damaged wiring or connectors
  • Poor ground connection
  • Malfunctioning transfer case control module
  • Short circuit in the wiring harness
  • Corroded terminals
  • Faulty instrument cluster
  • Issues with the transmission control module

Common misdiagnoses

  • Faulty transfer case switch
  • Wiring issues or shorts in the harness
  • Malfunctioning 4WD control module
  • Defective transmission control module
  • Incorrectly diagnosed transmission issues
  • Faulty dashboard indicator light
  • Issues with the transfer case itself
  • Problems with the vehicle's body control module (BCM)

Troubleshooting steps

  1. 1. Check the Vehicle's Manual

    Refer to the vehicle's service manual for specific information regarding the 4WD system and the P1805 code. This can provide insights into the wiring diagrams and component locations

  2. 2. Visual Inspection

    Inspect the wiring and connectors associated with the 4WD system, particularly those related to the 4WD High Indicator. Look for

  3. 3. Damaged or frayed wires

  4. 4. Corroded or loose connectors

  5. 5. Signs of wear or physical damage

  6. 6. Check the 4WD Switch

    Test the 4WD switch (if applicable) to ensure it is functioning correctly. This switch is often responsible for sending signals to the indicator light

  7. 7. Use a multimeter to check for continuity and proper operation of the switch

  8. 8. Inspect the Indicator Light

    Verify that the 4WD High Indicator light itself is functioning. If the bulb is burned out, it may not illuminate even if the circuit is working correctly

  9. 9. Test the Circuit

    Use a multimeter to check for voltage and continuity in the circuit

  10. 10. Check for an open circuit by testing the resistance between the connector pins. If there is no continuity, there may be a break in the wiring

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

    Some vehicles have a Transfer Case Control Module that manages the 4WD system. Check for any fault codes in this module and inspect its connections

  12. 12. Scan for Additional Codes

    Use an OBD-II scanner to check for any other related trouble codes that may provide additional context for the issue

  13. 13. Clear the Code and Test Drive

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

  14. 14. 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 Considerations - Ensure that the vehicle is in a safe and stable condition when performing any inspections or repairs. - Always disconnect the battery before working on electrical components to avoid short circuits or other electrical issues. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P1805 code