Mass Airflow Sensor
2021 Hyundai Tucson · 2.5L I4
Sensor Type
thermistor
Waveform Type
dc-variable
Location
Integrated into air intake duct between air filter housing and throttle body, driver side of engine bay
Pins
4-pin connector
Timebase
1s/div
Voltage Scale
1V/div
Trigger
2V, rising edge
Wiring
Pin 1: Signal output (yellow or white), Pin 2: Sensor ground (black), Pin 3: 12V power supply (red), Pin 4: IAT sensor signal (green or blue)
Expected Voltage Range
At Idle
0.8V to 1.4V
At Higher RPM
3.5V to 4.8V
Expected Pattern
Steady DC voltage at idle, smooth increase with throttle application proportional to airflow
Known-Good Waveform
At idle with engine fully warmed, expect 0.9-1.3V corresponding to 2-4 g/s airflow. Voltage should increase smoothly and linearly with throttle opening, reaching 3.8-4.5V at wide-open throttle. No fluctuations or noise greater than 0.05V should be present. During snap throttle, response should be immediate with no lag or steps in the voltage transition.
Common Failure Patterns
Voltage fixed at 0.2V or below 0.5V regardless of throttle position
Cause: Contaminated hot wire element from oil vapors or MAF sensor circuit short to ground
Voltage fixed above 4.8V or erratic jumping between values
Cause: Failed MAF sensor element, corroded connector pins, or circuit open/high resistance
Diagnostic Tips
Hyundai hot-film MAF sensors are sensitive to contamination from oiled aftermarket air filters and crankcase vapors. Always verify no air leaks between MAF and throttle body. Compare MAF voltage to calculated load (g/s) in scan data - voltage and airflow should correlate linearly. Do not clean with carb cleaner; use only MAF-specific cleaner.
Related Diagnostic Trouble Codes
P0100P0101P0102P0103P0104
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
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