P0100 Mass air flow sensor A circuit
What P0100 means
The engine computer is getting no usable signal from the mass air flow (MAF) sensor, which measures how much air enters the engine. Without it the computer estimates airflow from other sensors, so fuelling is less accurate and the engine may run poorly.
P0100 is a generic SAE J2012 code: it means the same on every make. The exact cause still depends on the car, so read the freeze-frame data before replacing parts.
At a glance
- Severity
- High
- Typical repair cost
- 40–350 €
- Workshop time
- 0.3–1.5 h
- Repair difficulty
- Easy
- DIY possible
- Yes
- Check engine light
- Yes
- Affects emissions test
- Yes
Parts and labour at an independent workshop in Europe. Main dealers charge more; the cause decides the bill, not the code.
Symptoms
- Check engine light on
- Hesitation or poor acceleration
- Rough idle or stalling
- Reduced power, sometimes limp mode
- Black smoke on diesels
Common causes
- Unplugged, loose or corroded MAF sensor connector
- Damaged wiring in the MAF power, ground or signal circuit
- Failed MAF sensor
- Blown fuse supplying the MAF sensor
Can I keep driving with P0100?
Get it to a workshop within a few days. The engine runs on estimated values, so drivability is poor and it can stall at junctions or hesitate when pulling out.
What to check first
- Check that the MAF connector is fully seated and look for corrosion or bent pins.
- With the key on, check for supply voltage and a good ground at the MAF connector.
- Read the live MAF value at idle and when revving; a signal that stays at zero or does not change points to the sensor or signal wire.
- If power, ground and signal wiring are good, replace the MAF sensor and clear the code.
Related codes
- P0101 Mass air flow sensor A range/performance
- P0102 Mass air flow (MAF) sensor A circuit low
- P0103 Mass air flow sensor A circuit high
- P0104 Mass air flow sensor A circuit intermittent
- P0105 Manifold absolute pressure / barometric pressure sensor circuit
- P0106 Manifold absolute pressure / barometric pressure sensor range/performance
- P0107 Manifold absolute pressure / barometric pressure sensor circuit low
- P0108 Manifold absolute pressure / barometric pressure sensor circuit high
Data: TORKO fault-code catalogue, built on OBDex (CC0-1.0) and reviewed against workshop practice. Informational only — it does not replace a diagnosis by a mechanic.
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