P0101
Mass or Volume Air Flow Circuit Range/Performance
The mass air flow (MAF) sensor signal is outside the expected range or does not track engine load plausibly. The ECU compares MAF readings against load calculated from RPM, throttle position and intake pressure; persistent disagreement triggers this code.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: easy
What we see in the workshop
ON FORD ECOBOOST
MAF range or performance faults on an EcoBoost are frequently caused by an aftermarket intake, a dirty sensor element, or a boost leak between the MAF and turbo inlet. We verify airflow against expected before replacing the sensor.
Common causes
Ordered by how often each turns out to be the cause.
- MAF sensor contaminated (oil, dust)Common
- Unmetered air leak after MAFPossible
- Air filter heavily cloggedPossible
- Wiring/connector fault to MAFLess likely
Parts involved
- Mass Air Flow Sensor
- Air Filter
- Intake Duct
- Intake Manifold
P0101 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.