WOMS
B code body Medium severity

B1690 Autolamp Delay Circuit Open

The OBD2 code B1690 indicates a malfunction in the autolamp delay circuit, specifically that the circuit is open, meaning there is a break in the electrical connection preventing proper operation

Definition

The OBD2 code B1690 indicates a malfunction in the autolamp delay circuit, specifically that the circuit is open, meaning there is a break in the electrical connection preventing proper operation

Common causes

  • Faulty autolamp relay
  • Open circuit in wiring
  • Bad connection or corroded terminals
  • Defective body control module (BCM)
  • Malfunctioning light sensor
  • Blown fuse
  • Faulty autolamp switch

Common misdiagnoses

  • Faulty headlight switch
  • Bad body control module (BCM)
  • Wiring issues or shorts in the circuit
  • Defective autolamp sensor
  • Malfunctioning relay
  • Battery or charging system problems
  • Incorrectly installed aftermarket lighting systems

Troubleshooting steps

  1. 1. Check the Vehicle's Manual

    Refer to the vehicle's service manual for specific information about the autolamp delay circuit and its components

  2. 2. Visual Inspection

  3. 3. Inspect the wiring and connectors associated with the autolamp system for any signs of damage, corrosion, or loose connections

  4. 4. Look for frayed wires or broken connectors that could cause an open circuit

  5. 5. Check Fuses

  6. 6. Locate and inspect the fuses related to the autolamp system. Replace any blown fuses and check if the code returns

  7. 7. Test the Autolamp Relay

  8. 8. If your vehicle uses a relay for the autolamp system, test the relay to ensure it is functioning properly. You can swap it with a similar relay in the fuse box to see if the problem persists

  9. 9. Inspect the Autolamp Sensor

  10. 10. If your vehicle has a light sensor, check its operation. Ensure it is clean and unobstructed, as a malfunctioning sensor can affect the autolamp system

  11. 11. Check the Control Module

  12. 12. The Body Control Module (BCM) or similar control unit may be responsible for the autolamp function. Check for any software updates or faults in the module

  13. 13. Use a Multimeter

  14. 14. Use a multimeter to check for continuity in the wiring associated with the autolamp delay circuit. Look for any breaks in the circuit that could indicate an open condition

  15. 15. Scan for Additional Codes

  16. 16. Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues

  17. 17. Clear the Code

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

  19. 19. Consult a Professional

  20. 20. If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with your specific vehicle make and model. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the B1690 code