Ignition Coil Primary
2012 Ford F-150 · 3.5L V6 EcoBoost
Sensor Type
inductive
Waveform Type
pulse-width
Location
Coil-on-plug configuration, directly mounted on each spark plug in the valve cover, six individual coils total
Pins
3-pin connector
Idle Frequency
25 Hz
Timebase
10ms/div
Voltage Scale
50V/div
Trigger
5V, falling edge
Wiring
Pin 1: Black/White (Ground), Pin 2: Brown/Yellow (12V Switched Power), Pin 3: Gray or Light Green (PCM Trigger Signal)
Expected Voltage Range
At Idle
0V to 14V
At Higher RPM
0V to 14V
Expected Pattern
Square wave switching pattern with coil saturation time of 2-3ms followed by rapid collapse spike to approximately 200-350V on primary side
Known-Good Waveform
Primary waveform should show clean 12-14V saturation period followed by sharp negative spike to 200-350V during coil collapse, then oscillating decay pattern. Dwell time increases with RPM. Current limiting by PCM maintains consistent saturation time of approximately 2-3ms at idle.
Common Failure Patterns
Reduced or absent voltage spike during collapse, weak oscillation pattern, extended saturation time
Cause: Internal coil short or open windings, common on cylinders 1 and 6 due to heat exposure
Diagnostic Tips
EcoBoost coils are prone to failure due to high turbo heat. Always check for oil contamination in spark plug wells which accelerates coil failure. Use current clamp to verify 6-8A draw during saturation.
Related Diagnostic Trouble Codes
P0351P0352P0353P0354
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
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