P0102: Mass Air Flow (MAF) Sensor Circuit Low Input
Updated November 12, 2026
The MAF sensor's signal is lower than it should ever be, which usually points to an electrical problem: the sensor, its connector or its wiring.
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🔧 Want to check this yourself? An OBD2 scanner reads the code; models with live data also show the sensor readings used in the checks below. See code readers and scanners from $24.99 ↓ · Which scanner do I need?
Common causes
- A disconnected, loose or corroded MAF connector
- Damaged wiring or a blown fuse feeding the sensor
- A failed MAF sensor
- A shorted signal wire or a poor sensor ground
Code meanings can vary slightly by manufacturer. Use these as a starting point and confirm with your vehicle's service information or a mechanic before replacing parts.
Symptoms
- Check engine light
- Hard starting, stalling or rough idle
- Reduced power
Is it safe to drive?
Often drivable, but the engine may stall or run poorly. Have it checked before a long trip.
How to check it with a scanner
- Plug an OBD2 scanner into the port under the dashboard and read all stored codes and the freeze-frame data (the conditions when the code set).
- Check the connector is fully seated and free of corrosion.
- With a scan tool, see if the MAF reading is near zero with the engine running.
- Test power, ground and signal at the connector against your vehicle's wiring diagram.
- After a repair, clear the code and drive normally for a few days to confirm it doesn't come back.
A basic code reader shows the code; scanners with live data let you watch sensor readings, which is what you need for most of the checks above. See OBD2 scanners under $100.
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Questions
What does P0102 mean?
P0102 is the generic OBD2 code for "Mass Air Flow (MAF) Sensor Circuit Low Input." The MAF sensor's signal is lower than it should ever be, which usually points to an electrical problem: the sensor, its connector or its wiring.
Is it safe to drive with P0102?
Often drivable, but the engine may stall or run poorly. Have it checked before a long trip.
How do I check P0102 myself?
Read the code and freeze-frame data with an OBD2 scanner, then: Check the connector is fully seated and free of corrosion. With a scan tool, see if the MAF reading is near zero with the engine running. Test power, ground and signal at the connector against your vehicle's wiring diagram.
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