Ignition Coil Primary
2022 Ford F-150 · 3.5L V6 EcoBoost
Sensor Type
inductive
Waveform Type
pulse-width
Location
Coil-on-plug assemblies mounted directly on spark plugs in valve covers, 6 individual coils
Pins
2-pin connector
Idle Frequency
25 Hz
Timebase
10ms/div
Voltage Scale
5V/div with 100V range capability
Trigger
5V, falling edge
Wiring
Black/White (ground) and various trigger wires from PCM (varies by cylinder position)
Expected Voltage Range
At Idle
0V to 14V
At Higher RPM
0V to 14V
Expected Pattern
Square wave with initial battery voltage, sharp drop during dwell, then voltage spike to 250-400V during coil collapse
Known-Good Waveform
Primary waveform shows clean battery voltage during off-time, stable dwell period of 2.5-3.5ms at idle, sharp voltage drop to near 0V when coil saturates, followed by inductive spike to 250-400V during firing. Dwell time increases with RPM and load, controlled by PCM based on battery voltage and combustion demands.
Common Failure Patterns
Reduced or absent voltage spike below 200V, extended dwell time
Cause: Weak coil with high primary resistance or shorted windings
Erratic dwell time or missing trigger pulses
Cause: PCM driver circuit failure or connector corrosion at coil
Diagnostic Tips
EcoBoost coils are known for heat-related failures due to turbocharger proximity. Monitor all 6 cylinders simultaneously to identify pattern failures. Verify PCM ground integrity at engine block connections as poor grounds cause erratic dwell control.
Related Diagnostic Trouble Codes
P0351P0352P0353P0354
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
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