WOMS
B code body Medium severity

B1590 Autolamp Delay Increase Circuit Short To Ground

The OBD2 code B1590 indicates a fault in the autolamp delay increase circuit, specifically a short to ground condition, which means there is an unintended connection to the ground in the circuit that controls the delay...

Definition

The OBD2 code B1590 indicates a fault in the autolamp delay increase circuit, specifically a short to ground condition, which means there is an unintended connection to the ground in the circuit that controls the delay feature for the vehicle's automatic lighting system

Common causes

  • Shorted wiring or connectors
  • Faulty autolamp delay module
  • Damaged or corroded ground connections
  • Malfunctioning headlight switch
  • Issues with the body control module (BCM)
  • Incorrectly installed aftermarket accessories
  • Water intrusion or moisture in electrical connectors

Common misdiagnoses

  • Faulty headlight switch
  • Defective body control module (BCM)
  • Shorted wiring harness
  • Malfunctioning autolamp relay
  • Incorrectly installed aftermarket lighting
  • Faulty ambient light sensor
  • Bad ground connections

Troubleshooting steps

  1. 1. Check the Vehicle's Manual

    Refer to the vehicle's service manual for specific information regarding the Autolamp system and wiring diagrams

  2. 2. Visual Inspection

    Inspect the wiring and connectors associated with the Autolamp system. Look for signs of damage, corrosion, or loose connections

  3. 3. Check the fuse related to the Autolamp system to ensure it is not blown

  4. 4. Scan Tool Diagnosis

    Use an OBD-II scanner to confirm the presence of the B1590 code and check for any other related codes that may provide additional context

  5. 5. Clear the code and see if it returns after a short drive

  6. 6. Check for Short to Ground

    Use a multimeter to test the Autolamp Delay Increase Circuit for continuity to ground

  7. 7. Disconnect the Autolamp module (if applicable) and check the circuit for continuity. If there is continuity to ground, there may be a short in the wiring

  8. 8. Inspect the Autolamp Module

    If applicable, inspect the Autolamp control module for any signs of damage or failure

  9. 9. Test the module according to the manufacturer’s specifications to ensure it is functioning correctly

  10. 10. Check Related Components

    Inspect any related components, such as switches or sensors that may be part of the Autolamp system. Ensure they are functioning properly

  11. 11. Repair or Replace Faulty Components

    If you identify any damaged wiring, connectors, or components, repair or replace them as necessary

  12. 12. Ensure all connections are secure and free from corrosion

  13. 13. Recheck the System

    After making repairs, reconnect any disconnected components and clear the codes from the OBD-II system

  14. 14. Test the Autolamp system to see if the issue has been resolved and if the code reappears

  15. 15. Consult a Professional

    If the issue persists after following these steps, it may be necessary to consult a professional mechanic or technician who has experience with the specific vehicle make and model.Additional Tips: - Always ensure that you are working in a safe environment and take necessary precautions when dealing with electrical systems. - Document any changes or repairs made during the troubleshooting process for future reference. By following these steps, you should be able to diagnose and potentially resolve the issue related to the B1590 code