WOMS
C code chassis High severity

C1751 Vehicle Speed Sensor # 1 Output Circuit Short to Vbatt

The OBD2 code C1751 indicates that there is a short circuit in the output circuit of Vehicle Speed Sensor #1 to the vehicle's battery voltage (Vbatt), which can cause incorrect speed readings or sensor failure

Definition

The OBD2 code C1751 indicates that there is a short circuit in the output circuit of Vehicle Speed Sensor #1 to the vehicle's battery voltage (Vbatt), which can cause incorrect speed readings or sensor failure

Common causes

  • Shorted wiring or connectors
  • Faulty vehicle speed sensor
  • Corroded or damaged connectors
  • Poor ground connection
  • Malfunctioning powertrain control module (PCM)

Common misdiagnoses

  • Faulty Vehicle Speed Sensor
  • Wiring issues or shorts in the harness
  • Faulty Engine Control Module (ECM)
  • Faulty Transmission Control Module (TCM)
  • Incorrectly installed or damaged connectors
  • Issues with the ABS module
  • Problems with the wheel speed sensors
  • Faulty speedometer or instrument cluster
  • Calibration issues
  • Software glitches or updates needed in the vehicle's computer system

Troubleshooting steps

  1. 1. Understand the Code

    C1751 typically indicates that the vehicle speed sensor (VSS) is sending a signal that is too high, suggesting a short circuit to the battery voltage (Vbatt)

  2. 2. Check the Vehicle Speed Sensor (VSS)

    Visual Inspection: Inspect the VSS for any physical damage, corrosion, or loose connections

  3. 3. Connector Check

    Ensure that the wiring harness and connectors are secure and free from damage or corrosion

  4. 4. Test the VSS

    Resistance Check: Use a multimeter to measure the resistance of the VSS. Compare the readings to the manufacturer’s specifications

  5. 5. Voltage Check

    With the ignition on (engine off), check the voltage at the VSS connector. It should be within the specified range. If it’s too high, there may be a short circuit

  6. 6. Inspect Wiring and Connectors

    Wiring Inspection: Look for any signs of fraying, chafing, or damage to the wiring leading to the VSS

  7. 7. Short Circuit Check

    Use a multimeter to check for continuity between the VSS signal wire and the battery voltage. If there is continuity, there is likely a short

  8. 8. Check for Ground Issues

    Ensure that the VSS has a good ground connection. A poor ground can cause erratic sensor readings

  9. 9. Scan for Additional Codes

    Use an OBD-II scanner to check for any other related trouble codes that may provide additional context or indicate other issues

  10. 10. Inspect the Engine Control Module (ECM)

    If all else checks out, there may be an issue with the ECM itself. Check for any software updates or known issues with the ECM related to the VSS

  11. 11. Clear the Code and Test Drive

    After performing the checks and repairs, clear the code using an OBD-II scanner and take the vehicle for a test drive to see if the code returns

  12. 12. Seek Professional Help

    If you are unable to resolve the issue after following these steps, it may be best to consult a professional mechanic or technician who has experience with your specific vehicle make and model. By following these steps, you should be able to identify and resolve the issue related to the C1751 code effectively