WOMS
C code chassis Medium severity

C1918 Air Suspension Ride Height Select Switch Circuit Failure

The OBD2 code C1918 indicates a malfunction in the air suspension ride height select switch circuit, which may affect the vehicle's ability to adjust or maintain the proper ride height

Definition

The OBD2 code C1918 indicates a malfunction in the air suspension ride height select switch circuit, which may affect the vehicle's ability to adjust or maintain the proper ride height

Common causes

  • Faulty ride height select switch
  • Damaged wiring or connectors
  • Short circuit in the circuit
  • Open circuit in the circuit
  • Corroded terminals
  • Malfunctioning air suspension control module
  • Poor ground connection
  • Water intrusion or moisture damage

Common misdiagnoses

  • Faulty air suspension compressor
  • Defective height sensors
  • Wiring issues or shorts in the harness
  • Malfunctioning air suspension control module
  • Low air pressure in the suspension system
  • Incorrectly calibrated suspension system
  • Faulty ride height sensors
  • Issues with the vehicle's body control module (BCM)

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 Ride Height Select Switch

    Visual Inspection: Check the ride height select switch for any visible damage, corrosion, or loose connections

  3. 3. Functionality Test

    If possible, test the switch to ensure it is functioning correctly. You can use a multimeter to check for continuity when the switch is activated

  4. 4. Examine Wiring and Connectors

    Wiring Inspection: Look for damaged, frayed, or shorted wires in the circuit leading to the ride height select switch

  5. 5. Connector Check

    Ensure that all connectors are secure and free of corrosion. Clean any corroded connectors and ensure a tight fit

  6. 6. Check the Air Suspension Control Module

    Inspect the air suspension control module for any signs of damage or malfunction. If the module is faulty, it may not properly interpret the signals from the ride height select switch

  7. 7. Test the Air Suspension System

    Ensure that the air suspension system is functioning correctly. Check for leaks in the air lines, and verify that the air compressor is operational

  8. 8. Inspect Fuses and Relays

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

  9. 9. Perform a System Reset

    Sometimes, clearing the code and resetting the system can resolve temporary glitches. Use the OBD-II scanner to clear the code and see if it returns

  10. 10. Consult the Vehicle’s Service Manual

    Refer to the specific service manual for your vehicle model for any manufacturer-specific troubleshooting steps or wiring diagrams

  11. 11. Professional Diagnosis

    If the issue persists after performing the above steps, consider seeking help from a professional mechanic or technician who has experience with air suspension systems

  12. 12. Document Findings

    Keep a record of any tests performed, findings, and repairs made. This documentation can be helpful for future reference or if you need to consult a professional. By following these steps, you should be able to identify the cause of the C1918 code and take appropriate action to resolve the issue