P22F3 - Cylinder 7 Alternative Fuel Fuel Injector Control Circuit High
System
Powertrain (Engine & Gearbox)
Technical Description
The control module has detected a fault in the Cylinder 7 Alternative Fuel Fuel Injector Control Circuit High (P22F3). The signal is above the upper threshold, typically from an open circuit, poor connection, or a short to battery voltage. The fault is isolated to cylinder 7, positioned in the central engine thermal core. This directly impacts individual cylinder volumetric efficiency, firing synchronization, and dedicated harness branch loading.
Multimeter Test Points & Nominal Values
| Test Point / Component | Measurement | Nominal Target Range | Test Condition |
|---|---|---|---|
| Cylinder 7 Injector – Coil Resistance | Resistance (Ω) | 11.5 - 15.5 Ω (port) / 0.5 - 3.0 Ω (direct injection) | Connector disconnected at 20°C (cylinder 7) |
| Cylinder 7 Injector – Injection Pulse at 360° crank angle | Signal (ms) | 2.5 - 4.5 ms idle / 1.5 - 20 ms under load | Engine running |
| Cylinder 7 Injector – Supply Voltage | Voltage (V) | 11.8 - 14.4 V (port) / up to 65 - 90 V boost (direct) | Ignition ON / engine running |
Connector disconnected at 20°C (cylinder 7)
Engine running
Ignition ON / engine running
Oscilloscope Waveform Analysis
1 ms/div, 20 V/divPossible Causes
Open circuit on signal wire, spread terminal pin, or short to power feed at Cylinder 7 Alternative Fuel Fuel Injector Control Circuit High
Cylinder 7 isolated routing:Dedicated harness branch degradation and individual manifold runner variation on cylinder 7.
Chafed or pinched wiring harness along the signal path to Cylinder 7 Alternative Fuel Fuel Injector Control Circuit High
Internal mechanical wear or carbon deposits inside Cylinder 7 Alternative Fuel Fuel Injector Control Circuit High
Defective internal output driver or reference circuit in the control module for Cylinder 7 Alternative Fuel Fuel Injector Control Circuit High
Symptoms
5
Recommended Solution
Swap the component on cylinder 7 to cylinder 4 and clear DTCs to confirm if the fault follows the part.
Measure signal terminal voltage with ignition ON and sensor unplugged to determine if ECM pull-up is active or harness is shorted to 12V.
Verify loaded supply voltage and harness terminal pins at Cylinder 7 Alternative Fuel Fuel Injector Control Circuit High.
Check circuit continuity and ground-side voltage drop (< 0.05 V) for Cylinder 7 Alternative Fuel Fuel Injector Control Circuit High.
Perform fuel rail pressure-drop / balance test to identify leaking, stuck, or clogged injectors.
Mechanic's Tip
Pair a current clamp with your voltage channel on the scope. The distinct dip in the current ramp marks the physical pintle lift — no dip means the coil is energized but the needle is mechanically seized.