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C1203 ABS Outlet Valve Coil Rear Circuit Open

The OBD2 code C1203 indicates that there is an open circuit in the rear outlet valve coil of the ABS (Anti-lock Braking System), which can affect the operation of the ABS system

Definition

The OBD2 code C1203 indicates that there is an open circuit in the rear outlet valve coil of the ABS (Anti-lock Braking System), which can affect the operation of the ABS system

Common causes

  • Damaged or frayed wiring
  • Faulty ABS outlet valve coil
  • Poor electrical connections
  • Corroded connectors
  • Failed ABS control module
  • Blown fuse
  • Grounding issues

Common misdiagnoses

  • Faulty ABS module
  • Bad wheel speed sensor
  • Damaged wiring or connectors
  • Faulty brake pedal position sensor
  • Incorrectly diagnosed brake fluid level issues
  • Misinterpreted fault codes related to the ABS system
  • Issues with the power supply to the ABS system
  • Faulty hydraulic control unit (HCU)

Troubleshooting steps

  1. 1. Check the Code and Freeze Frame Data

    Use an OBD-II scanner to confirm the C1203 code is present

  2. 2. Review freeze frame data to understand the conditions under which the code was set

  3. 3. Visual Inspection

    Inspect the ABS module and wiring harness for any visible damage, corrosion, or loose connections

  4. 4. Check the connectors for the ABS outlet valve coil for signs of wear or damage

  5. 5. Test the ABS Outlet Valve Coil

    Use a multimeter to measure the resistance of the ABS outlet valve coil. Compare the reading to the manufacturer’s specifications

  6. 6. If the resistance is out of spec, the coil may be faulty and require replacement

  7. 7. Check for Open Circuits

    Inspect the wiring between the ABS module and the outlet valve coil for continuity. Look for any breaks or shorts in the wiring

  8. 8. Use a multimeter to check for continuity in the circuit. If there is an open circuit, repair or replace the damaged wiring

  9. 9. Inspect the ABS Module

    If the wiring and coil are in good condition, the issue may lie within the ABS module itself

  10. 10. Check for any signs of water intrusion or damage to the module

  11. 11. If possible, test the ABS module with a known good unit to see if the problem persists

  12. 12. Check Power and Ground

    Ensure that the ABS module is receiving the correct voltage and ground. Use a multimeter to check the power supply and ground connections

  13. 13. Repair any issues with power or ground connections

  14. 14. Clear the Code and Test Drive

    After performing repairs, clear the code using the OBD-II scanner

  15. 15. Take the vehicle for a test drive to see if the code returns. Monitor the ABS system for proper operation

  16. 16. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the ABS system for your specific vehicle make and model. There may be known issues or recalls that could provide additional guidance

  17. 17. Seek Professional Help

    If the issue persists after following these steps, consider consulting a professional mechanic or an automotive technician with experience in ABS systems.Additional Tips: - Always refer to the vehicle’s service manual for specific diagnostic procedures and specifications. - Safety first: If you are not comfortable working on the ABS system, it is advisable to seek professional assistance. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the C1203 code