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P0273 Cylinder 5 Injector Circuit Low

The OBD2 code P0273 indicates that there is a low voltage or an open circuit in the injector circuit for cylinder 5, which can lead to improper fuel delivery to that cylinder

Definition

The OBD2 code P0273 indicates that there is a low voltage or an open circuit in the injector circuit for cylinder 5, which can lead to improper fuel delivery to that cylinder

Common causes

  • Faulty fuel injector for cylinder 5
  • Open or shorted wiring in the injector circuit
  • Poor electrical connection or corroded terminals
  • Faulty engine control module (ECM)
  • Low fuel pressure
  • Faulty fuel injector driver in the ECM
  • Grounding issues in the injector circuit

Common misdiagnoses

  • Faulty fuel injector
  • Wiring issues or short circuits
  • Engine control module (ECM) failure
  • Fuel delivery problems
  • Vacuum leaks
  • Faulty fuel pump
  • Injector driver circuit issues
  • Low fuel pressure
  • Engine mechanical issues (e.g., compression problems)
  • Faulty ignition components

Troubleshooting steps

  1. 1. Check for Additional Codes

    Before proceeding, check for any other related trouble codes that may provide more context to the issue

  2. 2. Visual Inspection

  3. 3. Inspect the wiring and connectors for the injector on cylinder 5. Look for signs of damage, corrosion, or loose connections

  4. 4. Check the injector harness for any fraying or breaks

  5. 5. Test the Injector

  6. 6. Use a multimeter to measure the resistance of the injector. Compare the reading to the manufacturer's specifications. A reading that is too high or too low may indicate a faulty injector

  7. 7. If possible, swap the injector from cylinder 5 with another cylinder (e.g., cylinder 4) and see if the code follows the injector. If it does, the injector is likely faulty

  8. 8. Check the Injector Circuit

  9. 9. With the engine running, use a multimeter to check the voltage at the injector connector. You should see a pulsing voltage when the engine is running. If there is no voltage, the issue may be upstream in the circuit

  10. 10. Inspect the power and ground connections to the injector. Ensure that the injector is receiving the correct voltage and that the ground is solid

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

  12. 12. Check for any signs of damage or corrosion on the ECM connectors

  13. 13. If all other components check out, the ECM itself may be faulty. This is less common but can happen

  14. 14. Check for Short Circuits

  15. 15. Inspect the wiring for any shorts to ground or to other circuits that could cause low voltage readings

  16. 16. Test the Fuel System

  17. 17. Ensure that the fuel system is functioning properly. A clogged fuel filter or failing fuel pump can affect injector performance

  18. 18. Clear the Code and Test Drive

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

  20. 20. Consult a Professional

    If you are unable to resolve the issue after these steps, it may be best to consult a professional mechanic for further diagnosis. By following these steps, you should be able to identify and resolve the issue related to the P0273 code