P0102 means Mass or Volume Air Flow Circuit Low Input. The MAF sensor signal is lower than the computer considers possible, which usually means an electrical fault or a sensor reading almost no airflow. 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 P0102 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.
P0102 symptoms
- Hesitation, stalling or a no-start on some vehicles
- Rough idle
- Poor fuel economy or black smoke
Common causes of P0102
- Unplugged or damaged MAF connector
- Open circuit or poor ground in the wiring
- Failed or badly contaminated MAF sensor
- Large intake leak between the MAF and the throttle body
How to diagnose P0102
- Check that the connector is fully seated and the terminals are clean
- Check power, ground and signal at the connector with a meter
- Watch the MAF reading on a scan tool as engine speed rises
- Inspect the intake ducting after the sensor for cracks or a loose boot
Can you drive with P0102?
Usually drivable in a fallback mode, but performance suffers. Repair it soon.
P0102 tips
A connector that was not clicked fully home after air filter service is the most common cause of a sudden P0102. If the sensor has power and ground but the signal stays near zero with the engine running, the sensor has failed.
Will P0102 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 P0102 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 |
| P0103 | Mass or Volume Air Flow Circuit High Input |
| P0171 | System Too Lean (Bank 1) |
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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