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C1790 Air Suspension LR Air Spring/Shock Solenoid Output Circuit Failure

The OBD2 code C1790 indicates a failure in the output circuit for the left rear air spring or shock solenoid in the air suspension system, suggesting a malfunction in the electrical circuit or the solenoid itself

Definition

The OBD2 code C1790 indicates a failure in the output circuit for the left rear air spring or shock solenoid in the air suspension system, suggesting a malfunction in the electrical circuit or the solenoid itself

Common causes

  • Faulty air spring/shock solenoid
  • Damaged wiring or connectors
  • Short circuit in the solenoid circuit
  • Open circuit in the solenoid circuit
  • Failed air suspension control module
  • Corrosion or poor connections
  • Air suspension system leaks
  • Faulty relay or fuse related to the air suspension system

Common misdiagnoses

  • Faulty air spring or shock absorber
  • Wiring issues or shorts in the circuit
  • Bad air suspension compressor
  • Defective height sensors
  • Malfunctioning air suspension control module
  • Low air pressure in the system
  • Air leaks in the suspension system
  • Incorrectly calibrated suspension system

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are multiple issues

  2. 2. Inspect the Wiring and Connectors

    Visual Inspection: Check the wiring harness and connectors associated with the left rear air spring/shock solenoid for any signs of damage, corrosion, or loose connections

  3. 3. Continuity Test

    Use a multimeter to test for continuity in the wiring. Look for breaks or shorts in the circuit

  4. 4. Test the Solenoid

    Functionality Test: If accessible, test the solenoid itself to ensure it is functioning properly. You can apply direct power to the solenoid to see if it activates

  5. 5. Resistance Check

    Measure the resistance of the solenoid with a multimeter. Compare the reading to the manufacturer’s specifications

  6. 6. Check the Air Suspension Control Module

    Inspect the air suspension control module for any signs of damage or corrosion

  7. 7. If possible, perform a reset or reprogramming of the module to see if that resolves the issue

  8. 8. Inspect the Air Suspension System

    Check for leaks in the air suspension system, particularly around the left rear air spring. A leak can cause the system to malfunction

  9. 9. Ensure that the air spring is not damaged or excessively worn

  10. 10. Check the Fuses and Relays

    Inspect the fuses and relays associated with the air suspension system. Replace any blown fuses or faulty relays

  11. 11. Perform a System Calibration

    Some vehicles may require a calibration or reset of the air suspension system after repairs. Consult the vehicle’s service manual for specific procedures

  12. 12. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the air suspension system for your specific vehicle make and model. There may be known issues or recommended fixes

  13. 13. Professional Diagnosis

    If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership. They may have specialized diagnostic tools and experience with your vehicle

  14. 14. Document Findings

    Keep a record of any tests performed, findings, and 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 C1790 code and take appropriate action to resolve the issue