WOMS
C code chassis Medium severity

C1721 Air Suspension Height Sensor Power Circuit Open

The OBD2 code C1721 indicates that there is an open circuit in the power supply to the air suspension height sensor, which can prevent the sensor from functioning properly

Definition

The OBD2 code C1721 indicates that there is an open circuit in the power supply to the air suspension height sensor, which can prevent the sensor from functioning properly

Common causes

  • Faulty height sensor
  • Damaged wiring or connectors
  • Blown fuse
  • Poor ground connection
  • Corroded terminals
  • Short circuit in the wiring
  • Malfunctioning air suspension control module

Common misdiagnoses

  • Faulty air suspension compressor
  • Defective air suspension height sensor
  • Wiring issues or shorts in the harness
  • Bad ground connections
  • Malfunctioning air suspension control module
  • Incorrectly calibrated height sensor
  • Air leak in the suspension system
  • Low air pressure in the suspension system

Troubleshooting steps

  1. 1. Visual Inspection

    Wiring and Connectors: Check the wiring and connectors associated with the height sensor for any signs of damage, corrosion, or loose connections. Pay special attention to the harness leading to the height sensor

  2. 2. Sensor Condition

    Inspect the height sensor itself for physical damage or signs of wear

  3. 3. Check Fuses

    Locate the fuse associated with the air suspension system and check if it is blown. Replace it if necessary and see if the code returns

  4. 4. Test the Height Sensor

    Resistance Check: Use a multimeter to measure the resistance of the height sensor. Compare the readings to the specifications provided in the vehicle’s service manual

  5. 5. Voltage Check

    With the ignition on (engine off), check for voltage at the height sensor connector. You should see the appropriate voltage (usually around 5V or 12V, depending on the system). If there is no voltage, trace back to the power source

  6. 6. Check Ground Connections

    Ensure that the ground connection for the height sensor is secure and free of corrosion. A poor ground can lead to an open circuit

  7. 7. Inspect the Air Suspension Control Module

    If the wiring and sensor check out, the issue may lie within the air suspension control module. Check for any fault codes in the module and ensure it is functioning properly

  8. 8. Scan for Additional Codes

    Use an OBD-II scanner to check for any other related codes that may provide additional context or indicate other issues within the air suspension system

  9. 9. Perform a System Reset

    After addressing any issues found, clear the codes using an OBD-II scanner and take the vehicle for a test drive to see if the code returns

  10. 10. Professional Diagnosis

    If you are unable to resolve the issue after these steps, it may be best to consult a professional mechanic or technician who has experience with air suspension systems.Additional Tips: - Always ensure safety when working on vehicles, especially when dealing with electrical systems. - Keep in mind that some vehicles may have unique characteristics or additional components related to their air suspension systems, so always refer to the specific service manual for your vehicle model. By following these steps, you should be able to identify the cause of the C1721 code and take appropriate action to resolve it