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P code powertrain High severity

P0268 Cylinder 3 Injector Circuit High

The OBD2 code P0268 indicates that there is a high voltage or an open circuit in the injector circuit for cylinder 3, which may lead to improper fuel delivery to that cylinder

Definition

The OBD2 code P0268 indicates that there is a high voltage or an open circuit in the injector circuit for cylinder 3, which may lead to improper fuel delivery to that cylinder

Common causes

  • Faulty fuel injector for cylinder 3
  • Short circuit in the injector wiring
  • Open circuit in the injector wiring
  • Poor electrical connection or corroded terminals
  • Faulty engine control module (ECM)
  • High resistance in the injector circuit
  • Fuel injector driver issue in the ECM
  • Faulty fuel rail or fuel pressure issues

Common misdiagnoses

  • Faulty fuel injector
  • Wiring issues or short circuits
  • Engine control module (ECM) failure
  • Fuel delivery problems
  • Vacuum leaks
  • Ignition system issues
  • Compression problems
  • Injector driver circuit issues

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 for the issue

  2. 2. Visual Inspection

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

  3. 3. Check the wiring harness for any signs of wear or fraying that could cause a short circuit

  4. 4. Test the Injector

    Disconnect the injector connector for cylinder 3 and use a multimeter to measure the resistance of the injector. Compare the reading to the manufacturer's specifications

  5. 5. If the resistance is out of spec, the injector may be faulty and should be replaced

  6. 6. Check the Injector Circuit

    With the injector still disconnected, check the voltage at the connector while the engine is cranking or running. You should see a pulsing voltage signal

  7. 7. If the voltage is consistently high (above the specified range), there may be a short circuit in the wiring

  8. 8. Inspect the ECM

    If the wiring and injector are both functioning correctly, the issue may lie with the engine control module (ECM). Check for any signs of damage or corrosion on the ECM connectors

  9. 9. If possible, test the ECM with a known good unit to see if the problem persists

  10. 10. Check for Ground Issues

    Ensure that the ground connection for the injector circuit is secure and free of corrosion. A poor ground can cause high voltage readings

  11. 11. Perform a Voltage Drop Test

    Conduct a voltage drop test on the injector circuit to check for excessive resistance in the wiring. This can help identify any issues in the circuit

  12. 12. Clear Codes and Test Drive

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

  13. 13. Consult Repair Manual

    Refer to the vehicle's service manual for specific diagnostic procedures and specifications related to the injector circuit for cylinder 3

  14. 14. Seek Professional Help

    If you are unable to diagnose or resolve the issue, consider seeking assistance from a qualified mechanic or automotive technician. By following these steps, you should be able to identify the cause of the P0268 code and take appropriate action to fix the problem