Check Engine Code
P0100
Mass Air Flow (MAF) Circuit Malfunction
What P0100 means
P0100 is a general fault in the mass air flow sensor circuit — the sensor that measures how much air enters the engine so the ECM can match fuel to it. A bad or unplugged MAF, or a wiring problem, makes the ECM guess at fueling and run poorly.
Symptoms
- Check engine light on
- Rough idle, stalling, or hard starting
- Hesitation or lack of power on acceleration
- Noticeably worse fuel economy
- Black smoke or the smell of raw fuel
Likely causes (most common first)
- Dirty or failed MAF sensor element
- Unmetered air — a loose or cracked intake boot after the MAF
- Damaged MAF wiring or a corroded connector
- Very dirty air filter
- Vacuum leak downstream of the sensor
Can I keep driving?
Usually yes, gently. Start by cleaning the MAF with MAF-specific cleaner and checking the intake boot — that fixes P0100 more often than a new sensor.
Typical repair cost
DIY fixes can start near $0 (parts only). Shop repairs for P0100 typically run up to $350 depending on the underlying cause and vehicle. Start with the most common cause — Dirty or failed MAF sensor element — before throwing parts at it.
Recommended parts & tools for P0100
Our buyer’s guides cover the tools and parts that pair with AXLY:
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