Fuel Injector
2017 Toyota Corolla · 1.8L I4
Sensor Type
inductive
Waveform Type
dc-square
Location
Intake manifold, individual port injectors for each cylinder
Pins
2-pin connector
Idle Frequency
25 Hz
Timebase
5ms/div
Voltage Scale
20V/div
Trigger
5V, falling edge
Wiring
Brown (12V power from EFI relay), Black/White or Black/Red (ground control from ECM varies by cylinder)
Expected Voltage Range
At Idle
0V to 14V
At Higher RPM
0V to 14V
Expected Pattern
Peak and hold at battery voltage, sharp drop to ground during injection, negative inductive kick spike to 50-70V at turn-off
Known-Good Waveform
Injector waveform should show battery voltage (12-14V) when off, clean drop to ground when energized for 2-4ms at idle, followed by sharp negative spike to 50-70V as magnetic field collapses. Pulse width increases proportionally with engine load and remains consistent across all cylinders at steady state.
Common Failure Patterns
Reduced or absent inductive kick spike below 40V, slow voltage rise at turn-off
Cause: Shorted injector windings or failing internal coil, resistance below 11 ohms
Diagnostic Tips
2ZR-FE injectors should measure 11.6-12.4 ohms resistance. Compare all four injector waveforms simultaneously to identify outliers. Toyota injectors rarely fail electrically but develop flow issues from deposit buildup - check fuel trim data correlation.
Related Diagnostic Trouble Codes
P0200P0201P0202P0203P0204
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
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