P22F3 — Cylinder 7 Alternative Fuel Injector Control Circuit High

Diagnostic algorithm

1. Connect a capable scan tool, read and record related codes and freeze-frame data; clear the code and attempt to reproduce.
2. Visually inspect the injector harness and connector at cylinder 7 and along the harness to the ECM for damage, heat, or corrosion.
3. With ignition OFF, disconnect the cylinder 7 injector and measure coil resistance between injector terminals. Compare to specification. An open or very low (short) reading indicates a faulty injector.
4. With key ON (engine off) backprobe the injector control terminal. Observe voltage with no command and while commanding the injector with a scan tool. Note if the circuit stays at supply voltage when it should be pulled low.
5. Check for short-to-voltage: disconnect injector and measure voltage on harness pin to chassis ground. If battery voltage is present when injector is disconnected, suspect wiring short to battery or a failed high-side driver.
6. Check ECM/PCM ground and power supply connections and measure for proper reference voltages.
7. Swap the cylinder 7 injector with a known-good injector from another cylinder and re-scan. If the code moves to the other cylinder, replace the injector; if it stays on cylinder 7, suspect wiring or ECM.
8. If wiring and injector check good, test or replace the ECM driver output for cylinder 7 following manufacturer service procedures or consider ECM replacement/reprogramming if supported and all other causes excluded.
9. After repair, clear codes and perform a road test to verify the fault does not return.