P22D9

Code

Generic P — Powertrain

Cylinder 1 Alternative Fuel Injector Control Circuit/Open

Brand: Generic

Type: P — Powertrain

Views: UK: 22 EN: 59 RU: 31

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Open or short in the injector wiring harness for cylinder 1
Corroded, loose or damaged injector connector or terminal
Failed alternative-fuel injector (open internal coil)
Blown fuse or faulty fuel/injector relay supplying injector circuit
Poor or missing ground at injector or ECU
Faulty PCM/ECU driver output for cylinder 1

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Rough idle or engine misfire on cylinder 1
Reduced engine performance and drivability issues
Poor fuel economy and elevated exhaust emissions
Hard starting or extended crank times
Possible engine surging or hesitation under load

What to check

Read freeze frame data and stored DTCs with a scan tool; note conditions when fault set
Visual inspection of cylinder 1 injector connector, wiring and harness routing
Check for corrosion, bent pins, loose terminals, and water intrusion at connector
Verify fuses and relays for injector/fuel circuits
Backprobe injector connector and monitor supply voltage and driver signal with scope or DVOM/noid light
Measure injector coil resistance with the injector disconnected

Signal parameters

Injector coil DC resistance (typical range): ~2–16 Ω (consult vehicle spec for exact value)
Supply voltage at injector connector (key ON): ~Battery voltage (11–14.5 V)
Driver side when inactive: open/high (no pulse); when active: pulsed to ground by ECU (0 V pulses)
Pulse pattern: PCM commands pulsed waveform with duty cycle 0–100% depending on load; pulse width varies with engine conditions
Noid light should flash when injector is commanded; oscilloscope should show pulses when commanded by scan tool

Diagnostic algorithm

Confirm DTC and related codes with a scan tool; record freeze frame and readiness status.
Perform a careful visual inspection of cylinder 1 injector connector, wiring, and chassis/engine grounds. Repair obvious damage.
Check fuses/relays related to the injector/fuel system; replace if blown and retest.
With ignition OFF, unplug the injector harness and measure injector coil resistance; compare to spec. Replace injector if open or out of spec.
With connector connected, backprobe the supply pin (should be battery voltage with key ON) and the driver pin. Crank or command injector with scan tool; use a noid light or oscilloscope to confirm pulsed signal.
If supply is missing, trace supply circuit back to fuse/relay and repair. If driver pulses are absent, check continuity between driver pin and PCM; look for shorts to power/ground.
Check for short to battery or ground on the driver circuit using an ohmmeter and isolation techniques (remove connectors as necessary).
Swap cylinder 1 injector with a known-good injector from another cylinder (if identical) to see if the fault moves. If it moves, replace the injector.
If wiring and injector test good but no driver signal from PCM, inspect PCM harness and grounds. Consider PCM replacement only after verifying all external circuitry is good.
Clear codes and road test under similar conditions to confirm repair; rescan to ensure fault does not return.

Likely causes

Broken/open wire between cylinder 1 injector connector and PCM
Corroded/dirty connector at the injector (open contact)
Failed injector coil (open resistance)
Blown fuse or relay in injector supply circuit

Fault status

⚠️ Status

Cylinder 1 alternative-fuel injector control circuit/open — electrical fault detected in injector drive circuit; MIL on. Check wiring, connector, injector coil and PCM driver.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0 - 2.5 hours