WOMS
C code chassis Medium severity

C0128 Low Brake Fluid Circuit Low

The OBD2 code C0128 indicates that the brake fluid level is low, which may trigger a warning in the vehicle's system

Definition

The OBD2 code C0128 indicates that the brake fluid level is low, which may trigger a warning in the vehicle's system

Common causes

  • Low brake fluid level
  • Faulty brake fluid level sensor
  • Damaged or corroded wiring/connectors in the brake fluid circuit
  • Brake fluid leak in the system
  • Faulty brake master cylinder
  • Malfunctioning ABS module

Common misdiagnoses

  • Faulty brake fluid level sensor
  • Brake fluid leak
  • Faulty ABS module
  • Wiring issues or short circuits
  • Faulty brake master cylinder
  • Low brake fluid due to normal wear
  • Incorrect brake fluid type or contamination

Troubleshooting steps

  1. 1. Check Brake Fluid Level

  2. 2. Open the hood and locate the brake fluid reservoir

  3. 3. Check the fluid level against the minimum and maximum markings on the reservoir. If the fluid is low, top it off with the appropriate brake fluid type (usually DOT 3 or DOT 4, but check your owner's manual)

  4. 4. Inspect for Leaks

  5. 5. Look for any signs of brake fluid leaks around the brake lines, calipers, and the master cylinder. If you find any leaks, they will need to be repaired

  6. 6. Examine the Brake Fluid Reservoir

  7. 7. Inspect the brake fluid reservoir for cracks or damage that could cause fluid loss

  8. 8. Ensure that the reservoir cap is secure and not damaged

  9. 9. Test the Brake Fluid Level Sensor

  10. 10. The brake fluid level sensor is usually located in the brake fluid reservoir. Check the wiring and connector for any signs of damage or corrosion

  11. 11. Use a multimeter to test the sensor for proper operation. You can do this by disconnecting the sensor and checking for continuity or resistance as specified in the service manual

  12. 12. Check for Faulty Wiring or Connectors

  13. 13. Inspect the wiring harness and connectors leading to the brake fluid level sensor for any signs of wear, corrosion, or damage

  14. 14. Repair or replace any damaged wiring or connectors

  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 addressing any issues found, 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 the above steps, it may be necessary to consult a professional mechanic for further diagnosis. There could be more complex issues at play, such as problems with the ABS module or other brake system components. By following these steps, you should be able to identify and resolve the issue related to the C0128 code. Always refer to your vehicle's service manual for specific procedures and specifications