Ignition Coil Primary
2015 Ford F-150 · 3.5L V6 EcoBoost
Sensor Type
inductive
Waveform Type
pulse-width
Location
Coil-on-plug assembly mounted directly on spark plug in cylinder head, six individual coils (cylinders numbered 1-3 on passenger bank, 4-6 on driver bank)
Pins
2-pin connector
Idle Frequency
25 Hz
Timebase
10ms/div
Voltage Scale
50V/div
Trigger
5V, falling edge
Wiring
Red/Light Green (12V power feed from ignition), White/Blue or White/Orange (PCM switching ground control, varies by cylinder)
Expected Voltage Range
At Idle
0V to 14V
At Higher RPM
0V to 14V
Expected Pattern
Square wave with initial 12-14V charge period, followed by sharp voltage spike (80-250V) during coil collapse, then oscillating decay to ground
Known-Good Waveform
Primary waveform shows clean 12-14V dwell period of 2-4ms followed by sharp inductive kick spike reaching 80-250V as magnetic field collapses. Oscillations should dampen quickly to baseline with 3-5 clean rings. EcoBoost typically shows 3-3.5ms dwell at idle with fast switching transistor turn-off.
Common Failure Patterns
Low or no inductive kick spike (less than 60V), extended dwell time, no oscillations
Cause: Failed coil windings, shorted primary circuit, carbon tracking in coil boot
Excessive ringing or irregular oscillations after coil collapse, erratic dwell times
Cause: High resistance in primary circuit, corroded coil connector, failing PCM driver
Diagnostic Tips
EcoBoost coils are prone to failure from heat and oil contamination through valve cover. Always check spark plug wells for oil accumulation. Compare all six cylinders simultaneously to identify weak coils - dwell and spike height should be consistent across all cylinders.
Related Diagnostic Trouble Codes
P0351P0352P0353P0354
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
Free, no signup. View all waveforms for this vehicle