WOMS
C code chassis Medium severity

C1851 Air Suspension Warning Lamp Circuit Open

The OBD2 code C1851 indicates that there is an open circuit in the air suspension warning lamp circuit, meaning the system is not detecting the warning lamp as expected, which may affect the air suspension system's...

Definition

The OBD2 code C1851 indicates that there is an open circuit in the air suspension warning lamp circuit, meaning the system is not detecting the warning lamp as expected, which may affect the air suspension system's functionality

Common causes

  • Open circuit in the wiring
  • Faulty air suspension control module
  • Damaged connectors or terminals
  • Blown fuse
  • Faulty air suspension warning lamp
  • Grounding issues
  • Corroded wiring or connections

Common misdiagnoses

  • Faulty air suspension compressor
  • Defective air suspension control module
  • Broken or damaged wiring harness
  • Faulty air suspension height sensors
  • Low air pressure in the suspension system
  • Malfunctioning relay or fuse
  • Incorrectly calibrated suspension system
  • Issues 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 about the air suspension system and the warning lamp circuit. This can provide valuable insights into the components involved

  2. 2. Visual Inspection

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

  4. 4. Check the air suspension control module and the warning lamp for any physical damage

  5. 5. Check Fuses

  6. 6. Locate the fuse box and check for any blown fuses related to the air suspension system. Replace any blown fuses and see if the issue persists

  7. 7. Test the Warning Lamp

  8. 8. Verify that the warning lamp itself is functioning correctly. You can do this by applying power directly to the lamp to see if it illuminates

  9. 9. Scan for Additional Codes

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

  11. 11. Inspect the Air Suspension Control Module

  12. 12. Check the air suspension control module for proper operation. If you have access to a diagnostic tool, you can perform a module scan to see if it is communicating correctly

  13. 13. Check for Ground Issues

  14. 14. Ensure that the ground connections for the air suspension system are secure and free of corrosion. A poor ground can cause circuit issues

  15. 15. Test Circuit Continuity

  16. 16. Use a multimeter to test the continuity of the wiring in the air suspension warning lamp circuit. Look for any breaks or shorts in the wiring

  17. 17. Check for Short Circuits

  18. 18. Inspect the circuit for any short circuits that may be causing the open circuit condition. This can include checking for pinched wires or damaged insulation

  19. 19. Consult Technical Service Bulletins (TSBs)

  20. 20. Look for any TSBs related to the air suspension system for your specific vehicle make and model. Manufacturers may have issued guidance on common issues and fixes. 1

  21. 21. Replace Faulty Components

  22. 22. If you identify any faulty components (e.g., wiring, connectors, control module), replace them as necessary. 1

  23. 23. Clear Codes and Test Drive

  24. 24. After making repairs, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns. If the issue persists after following these steps, it may be advisable to consult a professional mechanic or technician who specializes in air suspension systems for further diagnosis and repair