Fuel Injector
2021 Hyundai Tucson · 2.5L I4
Sensor Type
inductive
Waveform Type
dc-variable
Location
Mounted in fuel rail, injecting into intake ports on intake manifold side of cylinder head
Pins
2-pin connector
Idle Frequency
20 Hz
Timebase
2ms/div
Voltage Scale
20V/div
Trigger
6V, falling edge
Wiring
Pin 1: Battery positive 12V supply (red or pink), Pin 2: PCM ground control (varies by cylinder: black, gray, blue, green)
Expected Voltage Range
At Idle
0V to 65V
At Higher RPM
0V to 65V
Expected Pattern
Battery voltage with sharp drop during injection, negative voltage spike at injector closing
Known-Good Waveform
At idle, injector pulse width of 2.5-3.5ms with battery voltage (13-14V) when off. Sharp drop to near 0V during injection event, followed by negative spike of -40V to -65V when injector closes due to inductive kickback. The closing spike indicates proper pintle seating and healthy coil winding. Current ramp should be smooth without steps or irregularities.
Common Failure Patterns
Low or absent closing spike (less than -20V), extended pulse width
Cause: Shorted injector windings or restricted injector nozzle causing reduced flow
Excessive closing spike (below -80V), erratic pulse width
Cause: High resistance in injector connector or partial open circuit in winding
Diagnostic Tips
Compare all four injector waveforms simultaneously - pulse width should be within 0.2ms of each other at idle. Hyundai GDI-related carbon buildup on intake valves is common after 50k miles; consider intake valve cleaning if pulse widths are progressively increasing over time despite proper MAF sensor operation.
Related Diagnostic Trouble Codes
P0200P0201P0202P0203P0204
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
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