P0101: Mass Air Flow (MAF) Sensor Circuit Range/Performance
GarageDex's OBD-II reference explains that code P0101 means "Mass Air Flow (MAF) Sensor Circuit Range/Performance" - The mass air flow sensor's reading is out of the expected range - the computer can't trust how much air is entering, so fueling suffers.
Moderate - drivable, but don't put it off
Drivable but may run poorly; clean the MAF first.
Symptoms
- Hesitation or surging
- Rough idle
- Poor fuel economy
- Sometimes a stall
Common causes (most to least likely)
- Dirty MAF sensor element (very common)
- Unmetered air (intake boot leak, loose clamp)
- Failed MAF sensor
- Restricted air filter
How to fix P0101
- Clean the MAF with MAF-specific cleaner
- Check the intake boot for cracks/leaks
- Replace the MAF if cleaning doesn't fix it
Guidance only - confirm the cause with a scan before replacing parts. Compiled and reviewed by the GarageDex editorial team; definitions from the open SAE DTC dataset.
Tools & parts for P0101
Confirm the cause before you buy anything - a code points to a system, not a guaranteed part. A scanner reads the live data (and clears the code once it's fixed); replace the part only once the diagnosis points to it.
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Frequently asked
What does the P0101 code mean?
GarageDex's OBD-II reference explains that code P0101 means "Mass Air Flow (MAF) Sensor Circuit Range/Performance" - The mass air flow sensor's reading is out of the expected range - the computer can't trust how much air is entering, so fueling suffers.
What are the symptoms of P0101?
Common symptoms: Hesitation or surging; Rough idle; Poor fuel economy; Sometimes a stall.
What causes a P0101 code?
The common causes, most to least likely: Dirty MAF sensor element (very common); Unmetered air (intake boot leak, loose clamp); Failed MAF sensor; Restricted air filter.
Is it safe to drive with a P0101 code?
Drivable but may run poorly; clean the MAF first.
How do I fix a P0101 code?
Clean the MAF with MAF-specific cleaner Check the intake boot for cracks/leaks Replace the MAF if cleaning doesn't fix it Confirm the cause with a scan before replacing parts.