P0100 to P0104: mass air flow sensor
The sensor that measures the air entering the engine is out of range (P0101), reading low or high (P0102, P0103), intermittent (P0104) or has a circuit fault (P0100).
SeverityModerateUsually not urgent today, but it can get worse if left.
Can you keep driving?Drive gently, check it soonWhat does P0101 mean?
The mass air flow sensor tells the computer how much air is coming in so it can add the right amount of fuel. For P0101, the computer has compared the sensor with what it expects from engine speed, throttle opening and manifold pressure, and the figures do not agree. The circuit codes mean the signal is outside any voltage it should ever have.
What causes P0101?
- A dirty sensor element, often after an oiled air filter or a lot of dust
- An air leak between the sensor and the throttle
- A blocked air filter or intake
- Wiring or connector faults, for P0102 and P0103
- A failed sensor
What to check first for P0101
- Look at the air filter and the intake ducting for leaks or blockage
- Clean the sensor with a spray made for air flow sensors, never by touching the element
- Check the connector and the wiring
- Compare the reading on a scan tool with the expected value at idle
Can you drive with P0101?
Usually safe to drive to a workshop, though the engine may hesitate, idle unevenly or use more fuel. If it drops into a reduced-power mode, keep the drive short.
Since May 2018 an engine warning light that stays on is a major defect at the MOT, so the car fails until the fault is fixed.
Codes on this page
- P0100Mass or Volume Air Flow Circuit
- P0101Mass or Volume Air Flow Circuit Range/Performance
- P0102Mass or Volume Air Flow Circuit Low Input
- P0103Mass or Volume Air Flow Circuit High Input
- P0104Mass or Volume Air Flow Circuit Intermittent
Related codes
Checked on · Rafael Soares
These are the generic meanings every manufacturer shares. Each brand adds its own detail, so your car's handbook, its service information and a qualified mechanic have the last word. OdoKeep has no connection with any manufacturer, and the app does not read codes from the car.
