Mass Airflow Sensor
2021 Ford F-150 · 3.5L V6 EcoBoost
Sensor Type
thermistor
Waveform Type
dc-variable
Location
Intake air tube between air filter housing and turbocharger compressor inlet, passenger side of engine
Pins
4-pin connector
Timebase
1s/div for idle monitoring, 500ms/div for throttle snap test
Voltage Scale
1V/div
Trigger
Not applicable, DC signal
Wiring
Gray/Orange (MAF signal to PCM), Red/Light Blue (12V reference), Black (signal ground), Tan/Light Blue (IAT signal)
Expected Voltage Range
At Idle
0.6V to 1.2V
At Higher RPM
3.5V to 4.8V
Expected Pattern
Smooth analog voltage that increases linearly with airflow, should respond immediately to throttle changes without steps or dropouts
Known-Good Waveform
Hot-wire MAF outputs smooth DC voltage: 0.6-1.2V at idle (15-25 g/s airflow), rising smoothly to 1.8-2.5V at part throttle cruise, and 3.5-4.8V at wide-open throttle under boost (250-350 g/s). Signal should track throttle opening instantly with no hesitation, steps, or voltage dropouts. Voltage should return smoothly to idle level during deceleration without oscillation.
Common Failure Patterns
Voltage stuck at 0.4-0.6V regardless of throttle input or fluctuates erratically
Cause: Contaminated hot-wire element from oil vapor or debris, common with aftermarket air filters
Voltage signal contains regular oscillations or noise of 0.1-0.3V amplitude
Cause: Damaged sensing element or poor ground connection at MAF housing to intake tube
Diagnostic Tips
EcoBoost MAF must measure accurately pre-turbo as boost pressure calculations depend on it. Perform throttle snap test: voltage should rise smoothly from idle to 3V+ in under 0.5 seconds. Check for boost leaks or PCV system issues causing oily residue on hot-wire, which is the primary failure mode on these engines.
Related Diagnostic Trouble Codes
P0100P0101P0102P0103P0104
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
Free, no signup. View all waveforms for this vehicle