WOMS
P code powertrain Medium severity

P0813 Reverse Output Circuit

The OBD2 code P0813 indicates a malfunction in the reverse output circuit, which typically involves issues with the transmission's ability to detect when the vehicle is in reverse gear

Definition

The OBD2 code P0813 indicates a malfunction in the reverse output circuit, which typically involves issues with the transmission's ability to detect when the vehicle is in reverse gear

Common causes

  • Faulty transmission control module (TCM)
  • Damaged wiring or connectors in the reverse output circuit
  • Failed reverse switch or sensor
  • Short circuit in the wiring
  • Open circuit in the wiring
  • Poor ground connection
  • Malfunctioning transmission solenoid
  • Internal transmission failure

Common misdiagnoses

  • Transmission control module (TCM) failure
  • Faulty transmission range sensor
  • Wiring issues or shorts in the reverse output circuit
  • Defective neutral safety switch
  • Incorrectly diagnosed transmission problems
  • Malfunctioning vehicle speed sensor
  • Issues with the engine control module (ECM)

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide more context and help identify related issues

  2. 2. Inspect Wiring and Connectors

  3. 3. Visually inspect the wiring and connectors associated with the transmission control module (TCM) and the reverse output circuit

  4. 4. Look for signs of damage, corrosion, or loose connections. Pay special attention to the wiring harness that connects to the transmission

  5. 5. Test the Reverse Switch

  6. 6. The reverse switch (or reverse light switch) is responsible for sending a signal to the TCM when the vehicle is in reverse

  7. 7. Test the switch for proper operation using a multimeter. Ensure that it is functioning correctly and that it is not stuck in the "on" or "off" position

  8. 8. Check Transmission Fluid Level and Condition

  9. 9. Low or dirty transmission fluid can cause shifting issues and may affect the operation of the reverse circuit

  10. 10. Check the fluid level and condition, and replace or top off the fluid as necessary

  11. 11. Inspect the Transmission Control Module (TCM)

  12. 12. If the wiring and switch are in good condition, the issue may lie with the TCM itself

  13. 13. Check for any signs of damage or corrosion on the TCM connectors. If necessary, test the TCM for proper operation

  14. 14. Perform a Visual Inspection of the Transmission

  15. 15. Inspect the transmission for any signs of physical damage or leaks that could affect its operation

  16. 16. Ensure that all components are securely mounted and that there are no obstructions

  17. 17. Check for Ground Issues

  18. 18. Ensure that the TCM and related components have a good ground connection. Poor grounding can lead to erratic behavior and fault codes

  19. 19. Clear Codes and Test Drive

  20. 20. After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner

  21. 21. Take the vehicle for a test drive to see if the code returns. Monitor the transmission's performance during the drive

  22. 22. Consult a Professional

  23. 23. If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or transmission specialist for further diagnosis and repair. By following these troubleshooting steps, you can identify and resolve the issue associated with the P0813 code. Always refer to the vehicle's service manual for specific procedures and specifications related to your make and model