Fuel & air metering · Powertrain · generic (SAE-defined)
P0102: Mass or Volume Air Flow Circuit Low Input
P0102 means the mass air flow (MAF) sensor signal is lower than the engine computer considers possible, often pointing to an electrical problem with the sensor or its wiring.
Standard title per SAE J2012 / ISO 15031-6 · Updated 2026-11-07 · By CarWhere Research
How P0102 sets
The powertrain control module (PCM) monitors the MAF signal, which may be a voltage or frequency. If it stays below the lowest plausible value for a set time while the engine is running, P0102 sets. Typical causes are an open signal wire, a missing power or ground, or a sensor that has failed. Exact limits are manufacturer-specific.
Common causes of P0102
Roughly most likely first; the actual cause depends on the vehicle and needs testing to confirm.
- Unplugged or corroded MAF connector
- Open or shorted-to-ground signal wire
- Loss of MAF power or ground
- Failed MAF sensor
- Heavily contaminated sensing element
- Large air leak after the sensor
P0102 symptoms
- Check engine light on
- Stalling after startup
- Hesitation or lack of power
- Rough idle
- Poor fuel economy
How P0102 is diagnosed
- Scan for codes and freeze frame; check for sensor supply codes
- Inspect the MAF connector for corrosion or bent terminals
- Verify power and ground at the connector
- Back-probe the signal and compare idle reading to specification
- Wiggle-test the harness while watching live data
- Replace the sensor if the circuit tests good but the signal stays low
Typical fixes for P0102
- Repair or reconnect the MAF connector
- Repair open or grounded wiring
- Restore a missing power or ground
- Replace the MAF sensor
- Repair large intake leaks
Replace parts only after testing confirms the cause — a code names the circuit or condition that failed a check, not necessarily the faulty part. We don’t publish per-repair prices; for what households actually spend on upkeep, see car repair costs.
Related codes & warning lights
P0102 FAQ
What does code P0102 mean?
P0102 means the mass air flow (MAF) sensor signal is lower than the engine computer considers possible, often pointing to an electrical problem with the sensor or its wiring. The standard definition is "Mass or Volume Air Flow Circuit Low Input."
Can I drive with a P0102 code?
In most cases yes for a short time, because the engine computer switches to an estimated airflow, but stalling and hesitation are common. Plan a repair soon.
Can a dirty MAF sensor cause P0102?
Heavy contamination can lower the reading, but P0102 is more often electrical. Cleaning is worth trying after the wiring is checked.
Why does my engine stall with P0102?
If the MAF under-reports airflow, the PCM supplies too little fuel, which can cause stumbling or stalling until it switches to its backup strategy.
Keep researching
Engine guides by brand (known issues, specs)
More fuel & air metering codes
Sources
- SAE J2012 — Diagnostic Trouble Code Definitions (standard code titles)
- ISO 15031-6 — Road vehicles: communication between vehicle and external equipment for emissions-related diagnostics, Part 6: Diagnostic trouble code definitions
- U.S. EPA — Vehicle Emissions Inspection and Maintenance (I/M) programs
- U.S. EPA, 40 CFR 86.1806-17 — Federal onboard diagnostics requirements for light-duty vehicles
- California Air Resources Board — On-Board Diagnostic (OBD) Program
General information written by CarWhere Research, not a diagnosis of your vehicle. Manufacturers can add their own sub-definitions and test conditions; confirm with the factory service information for your year, make and model. Before paying for a repair, check NHTSA for open recalls and your warranty booklet: federal law requires an emissions warranty on major emission-control parts such as the catalytic converter and engine computer.