Ignition Coil Primary
2011 Ford F-150 · 5.0L V8 Coyote
Sensor Type
inductive
Waveform Type
pulse-width
Location
Coil-on-plug assembly mounted directly on top of each spark plug, valve cover mounted (8 individual coils)
Pins
3-pin connector
Idle Frequency
13.3 Hz
Timebase
10ms/div
Voltage Scale
5V/div
Trigger
3V, falling edge
Wiring
Black/White stripe (ground), Light Blue/Orange or Tan/Orange (12V switched power), various colors for trigger signal from PCM (cylinder-specific)
Expected Voltage Range
At Idle
0V to 12.5V
At Higher RPM
0V to 12.5V
Expected Pattern
Square wave showing coil charge time (dwell) followed by rapid voltage spike when coil fires, then oscillation as field collapses. Dwell time approximately 3-4ms at idle.
Known-Good Waveform
Clean square wave transitioning from battery voltage to near ground during dwell period, followed by sharp downward spike to approximately -80V to -150V (inductive kick) when coil fires. After spike, clean dampened oscillations (3-5 ringing cycles) should be visible as magnetic field collapses. Pattern repeats every 75ms at idle (800 RPM).
Common Failure Patterns
Reduced or absent negative voltage spike, weak or no oscillations after coil fires
Cause: Failed coil with shorted or open primary windings, common on high-mileage 5.0L Coyote engines
Diagnostic Tips
Ford 5.0L Coyote coils are known to fail internally around 100k miles. Compare all 8 coil primary patterns simultaneously if possible. Check for oil contamination in spark plug wells which accelerates coil failure.
Related Diagnostic Trouble Codes
P0351P0352P0353P0354
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
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