WOMS
P code powertrain Medium severity

P1842 Transmission Transfer Case Differential Lock-Up Feedback Switch Circuit Failure

The OBD2 code P1842 indicates a malfunction in the transmission transfer case differential lock-up feedback switch circuit, which may affect the operation of the vehicle's four-wheel drive system

Definition

The OBD2 code P1842 indicates a malfunction in the transmission transfer case differential lock-up feedback switch circuit, which may affect the operation of the vehicle's four-wheel drive system

Common causes

  • Faulty differential lock-up feedback switch
  • Damaged wiring or connectors
  • Short circuit in the circuit
  • Open circuit in the circuit
  • Corroded terminals
  • Faulty transmission control module (TCM)
  • Malfunctioning transfer case
  • Low transmission fluid levels
  • Mechanical issues within the transfer case

Common misdiagnoses

  • Faulty transfer case
  • Defective transmission control module (TCM)
  • Wiring issues or shorts in the circuit
  • Malfunctioning differential lock actuator
  • Incorrectly diagnosed transmission fluid issues
  • Faulty vehicle speed sensor
  • Issues with the powertrain control module (PCM)
  • Problems with the ABS system
  • Misinterpretation of other OBDII codes
  • Mechanical issues in the drivetrain

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide more context and help identify related issues

  2. 2. Inspect the Wiring and Connectors

    Visually inspect the wiring and connectors associated with the differential lock-up feedback switch. Look for signs of damage, corrosion, or loose connections

  3. 3. Ensure that all connectors are securely attached and free of dirt or moisture

  4. 4. Test the Differential Lock-Up Feedback Switch

    Locate the differential lock-up feedback switch and test its operation. You can use a multimeter to check for continuity and proper voltage

  5. 5. If the switch is faulty, it may need to be replaced

  6. 6. Check the Transfer Case Control Module

    Inspect the transfer case control module for any signs of damage or malfunction. Ensure that it is receiving the correct signals from the feedback switch

  7. 7. If necessary, test the module according to the manufacturer's specifications

  8. 8. Inspect the Transfer Case

    Check the transfer case for any mechanical issues that could affect the operation of the differential lock-up system. Look for leaks, unusual noises, or signs of wear

  9. 9. Check for Ground Issues

    Ensure that the ground connections for the differential lock-up feedback switch and related components are secure and free of corrosion

  10. 10. Clear the Codes and Test Drive

    After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner

  11. 11. Take the vehicle for a test drive to see if the code reappears. Monitor the operation of the 4WD/AWD system during the drive

  12. 12. Consult the Service Manual

    Refer to the vehicle's service manual for specific diagnostic procedures and specifications related to the P1842 code. This can provide additional guidance tailored to your vehicle model

  13. 13. Seek Professional Help

    If the issue persists after performing these troubleshooting steps, it may be necessary to consult a professional mechanic or technician who has experience with your vehicle's specific system. By following these steps, you should be able to identify and resolve the issue related to the P1842 code