P0102Mass or Volume Air Flow Circuit Low Input

What it means

The mass-airflow sensor tells the computer how much air is entering the engine — the number every fueling decision is built on. P0102 means its signal is implausibly low or dead, which is nearly always electrical or contamination rather than a real lack of airflow. The computer falls back to estimating airflow, so the engine usually still runs — just not well.

Is it safe to drive?

Get it checked soon

The car will typically drive in fallback mode — expect hesitation, weak power, rough idle, and worse economy. It won't strand you in most cases, but fallback fueling is a guess, so don't leave it for long; lean, rich, and misfire codes tend to pile on if you do.

Common causes

Most likely first.

• A disconnected, corroded, or damaged MAF connector or its wiring
• A MAF element fouled by dirt — or oil from an over-oiled aftermarket air filter
• A failed MAF sensor
• Ducting problems around the sensor skewing what it can read

What the live data shows

MAF grams-per-second is the direct read: a healthy engine idles at a small, steady number — roughly 2–8 g/s on most passenger cars — climbing smoothly with revs. With P0102 it sits near zero or flatlines no matter the RPM. Cross-check calculated engine load and the fuel trims: trims swinging hard while the MAF reads nothing confirms the sensor, not the engine.

A scanner that reads all 139 standard sensors shows you these readings live. ScanMyCar charts them as you drive, keeps the freeze-frame stored with the code, and pulls codes from every module — free, with any cheap Bluetooth adapter.

Typical fixes

Cheapest first, where honesty allows.

• Unplug and reseat the MAF connector; look for bent pins and corrosion — free
• Clean the element with MAF cleaner (never touch it) — a few dollars
• Repair damaged wiring
• Replace the MAF sensor