WOMS
C code chassis Medium severity

C1791 Air Suspension LR Air Spring/Shock Solenoid Output Circuit Open

The OBD2 code C1791 indicates that there is an open circuit in the solenoid output for the left rear air spring or shock absorber in the air suspension system, which prevents proper operation of that component

Definition

The OBD2 code C1791 indicates that there is an open circuit in the solenoid output for the left rear air spring or shock absorber in the air suspension system, which prevents proper operation of that component

Common causes

  • Open circuit in the wiring
  • Faulty air spring/shock solenoid
  • Corroded or damaged connectors
  • Blown fuse
  • Faulty air suspension control module
  • Grounding issues

Common misdiagnoses

  • Faulty air spring or shock absorber
  • Bad air suspension compressor
  • Damaged wiring or connectors
  • Faulty air suspension control module
  • Low air pressure in the system
  • Air leaks in the suspension system
  • Incorrectly calibrated height sensors
  • Faulty relay or fuse related to the air suspension system

Troubleshooting steps

  1. 1. Check the Vehicle's Manual

    Refer to the vehicle's service manual for specific information related to the air suspension system and the C1791 code

  2. 2. Visual Inspection

    Wiring and Connectors: Inspect the wiring harness and connectors associated with the left rear air spring/shock solenoid. Look for signs of damage, corrosion, or loose connections

  3. 3. Air Spring/Shock Assembly

    Check the air spring or shock assembly for any visible damage or leaks

  4. 4. Scan Tool Diagnosis

    Use an OBD-II scanner to confirm the C1791 code and check for any additional codes that may provide more context

  5. 5. Clear the code and see if it returns after a short drive. If it does, proceed with further diagnostics

  6. 6. Test the Solenoid

    Resistance Check: Measure the resistance of the solenoid using a multimeter. Compare the reading to the specifications in the service manual. A reading outside the specified range may indicate a faulty solenoid

  7. 7. Power and Ground

    Check for proper voltage and ground at the solenoid connector while the system is activated. If there is no power or ground, trace the wiring back to the control module

  8. 8. Inspect the Control Module

    If the solenoid tests good, the issue may lie with the air suspension control module. Check for any fault codes in the module and inspect for proper operation

  9. 9. Ensure that the module is receiving power and ground

  10. 10. Check for Short Circuits

    Inspect the wiring for any signs of short circuits or grounding issues that could cause an open circuit condition

  11. 11. Test the Air Suspension System

    If applicable, perform a functional test of the air suspension system to ensure that it operates correctly. This may involve activating the system and observing the response of the left rear air spring/shock

  12. 12. Consult Technical Service Bulletins (TSBs)

    Look for any TSBs related to the air suspension system for your specific vehicle make and model. There may be known issues or recalls that could be relevant

  13. 13. Professional Diagnosis

    If the issue persists after performing these steps, consider seeking help from a professional mechanic or dealership with experience in air suspension systems

  14. 14. Document Findings

    Keep a record of all tests performed, findings, and any repairs made. This documentation can be helpful for future reference or if professional assistance is needed. By following these steps, you should be able to identify the cause of the C1791 code and take appropriate action to resolve the issue