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.
General code reference. Confirm the definition and diagnostic procedure for your vehicle's year, model and engine. A stored code alone does not identify a failed part.
Affected components
- Mass air flow sensor
- Air filter
- Intake duct
- Intake manifold
Possible causes to check
These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.
- MAF sensor contaminated (oil, dust)
- Unmetered air leak after MAF
- Air filter heavily clogged
- Wiring/connector fault to MAF
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
Sources
Check each reference's vehicle and model-year scope. General background links do not establish which fault is most likely on your vehicle.
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.