An integrated electronic module calculates the air mass from this temperature difference and transmits the result to the electronic engine control unit.Checked 2026-08-16
Mass airflow and MAP sensors
The MAF measures incoming air mass; the MAP sensor measures intake-manifold pressure.
Also called: MAF sensor · air-mass meter · MAP sensor · manifold pressure sensor
What it means
Definition
A mass airflow sensor measures the mass of air entering the engine. A manifold absolute pressure sensor measures pressure in the intake manifold. The engine computer uses these signals, with temperature and speed data, to calculate load and control fuel and boost; some engines use one sensor strategy and some use both.
Why a buyer cares
What it changes
MAF and MAP are related but not interchangeable. An air leak, wiring fault or implausible reading can produce a code that names the signal without proving the sensor itself has failed.
In practice
Where you meet it
In live scan-tool data and trouble codes containing MAF, air mass, MAP, manifold pressure or boost pressure.
Two things that look alike
Not the same as
The throttle controls airflow; these sensors measure conditions in the intake system.
Read next
Related terms
Powertrain Control Module (PCM)
The onboard computer that runs the engine and, on many cars, the transmission.
Diagnostic Trouble Code (DTC)
The code an OBD-II system stores to identify which monitored system it found a fault in.
Turbocharger
An exhaust-driven compressor that forces extra air into the engine.
Fuel injector
An electronically controlled valve that meters fuel into the intake port or combustion chamber.
Where this comes from
Sources
Manifold Absolute Pressure (MAP) sensors monitor intake manifold pressure to optimize fuel injection.Checked 2026-08-16
Sensor placement and the way calculated load is derived vary by engine-management design.