Ignition Coil Secondary
2016 Ford F-150 · 3.5L V6 EcoBoost
Sensor Type
inductive
Waveform Type
pulse-width
Location
Secondary output measured at coil tower or using capacitive pickup near spark plug wire boot on coil-on-plug assembly
Pins
Unknown
Idle Frequency
25 Hz
Timebase
5ms/div
Voltage Scale
5kV/div
Trigger
2kV, rising edge
Wiring
N/A - measured using high-voltage probe or capacitive pickup on coil boot
Expected Voltage Range
At Idle
-1000V to 35000V
At Higher RPM
-1000V to 40000V
Expected Pattern
Rapid voltage rise to firing spike (8-15kV typical), sharp drop to burn voltage plateau (1.5-3kV for 1-2ms), then coil oscillations and spark line
Known-Good Waveform
Secondary waveform shows firing line reaching 8-15kV under normal load with rapid rise time. Burn voltage should be stable at 1.5-3kV for approximately 1-2ms duration with minimal fluctuation. EcoBoost direct injection creates lean cylinder conditions requiring consistent spark energy. Coil oscillations after burn should show 3-5 clean peaks.
Common Failure Patterns
Firing line exceeds 20kV, extended burn time, irregular burn voltage
Cause: Worn spark plugs (gap too large), lean mixture, carbon tracking in coil boot, excessive plug gap from 100k+ miles
Intermittent or missing firing line, spark line shows no activity
Cause: Failed coil secondary windings, cracked coil case, severe carbon tracking, shorted coil boot
Diagnostic Tips
EcoBoost engines with direct injection are sensitive to spark plug condition - replace plugs at 60k mile intervals maximum. Ford specifies Motorcraft SP-546 or equivalent platinum plugs. Carbon tracking in coil boots is common due to oil intrusion; inspect boots carefully during coil testing.
Related Diagnostic Trouble Codes
P0300P0301P0302P0303
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
Free, no signup. View all waveforms for this vehicle