Mass air flow sensor
P0101
Mass or Volume Air Flow Circuit Range/Performance
The sensor that measures air going into the engine is reading outside its expected range, so the computer can't work out the right amount of fuel.
Fix it soon
Can I keep driving? For a short while, gently. Have it checked in the next few days, and stop if the car feels, sounds or smells different. It usually drives, with rough idle, hesitation or poor fuel economy. Fix it before it fouls the plugs or the catalytic converter.
What the words mean
- Range/Performance means the reading is believable electrically but doesn't match what the computer expects.
Common causes
- A dirty sensor element
- A dirty or wrongly fitted air filter
- An air leak between the sensor and the engine
- A failed sensor, or wiring trouble
Listed roughly from most to least likely. The same code can have different causes on different cars.
What to do
- Check the air filter and that the air box is closed all the way around.
- Check the intake hose for cracks and loose clamps.
- Clean the sensor with mass-air-flow cleaner only. Never touch the element.
- Replace the sensor if cleaning doesn't help.
General guidance. Your owner's manual wins. If a red warning light is on or the car drives differently, stop safely and get help.
Related codes
- P0100Mass or Volume Air Flow Circuit
- P0102Mass or Volume Air Flow Circuit Low Input
- P0103Mass or Volume Air Flow Circuit High Input
Track this automatically in Tagwell Auto
Tagwell Auto keeps your car's service dates and mileage, so when a code shows up you know what was done last. With a Bluetooth reader for the car's diagnostic port (called OBD-II), the phone app can read the code itself.