P1263 FORD – Cylinder #3 High to Low Side Short

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Meaning of FORD Code P1263

This code indicates a problem in the fuel injector circuit #3. Piezoelectric injectors deliver a precise amount of fuel into the combustion chamber. The PCM controls their activation (duration: 0 to 400 microseconds). If the injector interface module detects an anomaly in the secondary circuit (rear injector), code P1263 is displayed.


Symptoms of Code P1263

  • Check engine light on (or “Service Engine Soon”)

  • Rough idle

  • Loss of power

  • Increased fuel consumption

  • Misfires (especially on the affected cylinder)


Possible Causes of FORD P1263

  1. Faulty fuel injector #3

  2. Damaged injector #3 wiring harness (open circuit or short circuit)

  3. Poor electrical connection (corrosion, bent pins, loose connector)

  4. Faulty injector interface module

  5. Ground or power supply issue


Diagnosis and Repair of Code P1263

1. Visual inspection of the injector circuit

  • Check the wiring harness and connectors (especially under the valve cover).

  • Look for cut, burned, or exposed wires.

  • Inspect the connector pins (broken, bent, oxidized).

2. Testing injector #3

  • Measure the injector resistance (compare with manufacturer specifications).

  • Use an oscilloscope to check the control signal.

  • If faulty, replace the injector.

3. Checking the injector interface module

  • Test the module’s power supply and ground.

  • If necessary, replace the module.

4. PCM check

  • Check for related codes and real-time data with an OBD2 scanner.

  • If the problem persists, PCM reprogramming or replacement may be necessary.


Common Repairs

Replacement of faulty injector #3
Repair of damaged wiring harness
Cleaning or replacement of oxidized connectors
Replacement of injector interface module
PCM update or replacement


Conclusion

Code FORD P1263 indicates a problem in injector #3 circuit. A thorough inspection of wiring and connectors is essential before replacing expensive parts. If the problem persists, consult a specific repair manual or a qualified mechanic.

🔧 Technical tip: Use a multimeter and an oscilloscope for accurate diagnosis.

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