Fuel Injector
2021 Toyota Camry · 2.5L I4
Sensor Type
inductive
Waveform Type
pulse-width
Location
Port fuel injectors mounted in intake manifold, one per cylinder on intake side of cylinder head
Pins
2-pin connector
Idle Frequency
20.83 Hz
Timebase
10ms/div
Voltage Scale
20V/div
Trigger
6V, falling edge
Wiring
12V power supply (shared) - typically white or pink wire, ECM ground control - individual black or brown wires per injector
Expected Voltage Range
At Idle
0V to 65V
At Higher RPM
0V to 65V
Expected Pattern
Battery voltage baseline, sharp drop to 0V when injector energizes, inductive spike to 50-65V on closing, pulse width 2.5-4.5ms at idle
Known-Good Waveform
Clean rectangular pulse starting at battery voltage, dropping instantly to near 0V during injector opening with pulse width of 2.5-4.5ms at warm idle. Sharp inductive kickback spike to 50-65V when ECM switches off, indicating proper pintle closure. All four injectors should show nearly identical pulse widths and timing patterns during steady-state idle.
Common Failure Patterns
Pulse width significantly longer on one cylinder (>1ms difference), or erratic pulse width variation
Cause: Partially clogged injector requiring longer open time to maintain fuel delivery, or weak injector spring
Reduced or absent inductive spike below 40V, slower voltage transitions
Cause: High resistance in injector winding or connector corrosion, partial internal short
Diagnostic Tips
Toyota's D-4S system on some Camry variants uses both port and direct injection - verify you're testing port injectors (lower pressure). Normal resistance is 13-16 ohms. Compare all four injector patterns simultaneously; injector flow imbalance is common on high-mileage engines.
Related Diagnostic Trouble Codes
P0200P0201P0202P0203P0204
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
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