P0100 means Mass or Volume Air Flow Circuit Malfunction. The computer has found a general fault in the mass air flow (MAF) sensor circuit, so it cannot measure how much air the engine is taking in. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0100 means
Most engine sensors receive a 5-volt reference and return a signal between roughly 0 and 5 volts. Codes ending in circuit high or circuit low usually point to an electrical fault: an open circuit, a short or an unplugged connector. Range/performance codes mean a signal is present but disagrees with what the computer expects from the other sensors, which more often points to a dirty sensor, an air leak or a mechanical problem.
P0100 symptoms
- Rough idle or stalling
- Hesitation
- Poor fuel economy
- Check engine light
Common causes of P0100
- Failed or contaminated MAF sensor
- Unplugged or corroded connector
- Wiring fault
- Air leak after the sensor
How to diagnose P0100
- Inspect the MAF connector and wiring
- Check the sensor’s grams-per-second reading at idle
- Check the intake ducting for leaks
Can you drive with P0100?
Usually for short trips; drivability may suffer.
P0100 tips
Never clean a MAF sensor with anything but a cleaner made for it, and do not touch the sensing element.
Will P0100 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0100 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0101 | Mass or Volume Air Flow Circuit Range/Performance |
| P0102 | Mass or Volume Air Flow Circuit Low Input |
| P0103 | Mass or Volume Air Flow Circuit High Input |
Guides that help
When it is more than a sensor
Sensor codes are usually fixed with a sensor, a connector, wiring or a leak repair rather than major parts. If testing turns up internal engine trouble instead, see how to tell if an engine is blown and compare engines by code on our engines page.
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