Fuel Injector
2021 Honda Civic · 1.5L I4 Turbo
Sensor Type
inductive
Waveform Type
pulse-width
Location
Port fuel injectors mounted in intake manifold fuel rail, firing into intake ports
Pins
2-pin connector
Idle Frequency
25 Hz
Timebase
5ms/div
Voltage Scale
20V/div
Trigger
5V, falling edge
Wiring
Yellow (12V constant power) and Pink, Light Green, Blue, or Brown (ECM ground trigger, varies by cylinder)
Expected Voltage Range
At Idle
0V to 65V
At Higher RPM
0V to 70V
Expected Pattern
Sharp voltage spike to 55-65V when injector closes (inductive kickback), square wave during 2-4ms pulse width at idle
Known-Good Waveform
Clean square wave with rapid voltage drop from 12V to near 0V when ECM grounds the injector, holding at ground for pulse width duration (2-4ms at idle, increasing with load). When injector closes, inductive kickback spike reaches 55-70V for 0.2-0.5ms before settling back to 12V. Consistent pulse width across all four injectors indicates balanced fuel trim.
Common Failure Patterns
Reduced or absent kickback spike below 40V, slow closing ramp
Cause: Shorted injector coil windings or contaminated pintle preventing full closure
Diagnostic Tips
The L15B7 uses direct injection in addition to port injection on some models; verify you're testing the correct system. These Denso injectors commonly develop varnish buildup causing rich conditions; look for pulse width below 2ms at warm idle indicating ECM compensating with negative fuel trim.
Related Diagnostic Trouble Codes
P0200P0201P0202P0203P0204
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
Free, no signup. View all waveforms for this vehicle