A mass air flow (MAF) sensor, is one of the key components, of an electronic fuel injection system.

It is located, between the air filter and the intake manifold of the engine.

In most modern cars, they will also have, a intake air temperature (IAT) sensor, built into the (MAF). There are a few types, of air flow sensors, however, modern cars use a (hot-wire) type.

Firstly, the mass air flow (MAF) sensor measures, the amount of air, entering the engine.

A hot-wire (MAF) sensor, has a small electrically heated wire (hot wire). A temperature sensor installed close to the hot wire, measures the temperature of the air near the hot wire.

So, when the engine is idling, a small amount of air, flows around the (hot wire). Consequently, it takes a very low electric current, to keep the wire hot. However, when you press the gas, the throttle opens, letting more air to flow over the (hot wire).

As a result, the passing air, cools the wire down. So, the more air that flows over the wire, the higher the electrical current must be. Therefore, the electric current, is proportional to the amount of air flow. A small electronic chip, installed inside the mass air flow sensor, translates the electric current, into a digital signal.

And, then sends it, to the engine computer (PCM). The (PCM) uses the air flow signal, to calculate, how much fuel to inject. So, the goal is, to keep the air fuel ratio, at the optimal level.

Rough engine idle, can also be a problem.

So, a contaminated or failed mass air flow (MAF) sensor cannot measure the amount of air flow correctly. This causes the engine computer to miscalculate the amount of injected fuel. As a result, a bad (MAF) sensor, causes various driveability problems. And, includes a no-start, stalling, lack of power and poor acceleration. In addition, a faulty (MAF) sensor might cause the Check Engine light to come on. A problem with the (MAF) sensor could also alter the shifting pattern of the automatic transmission.

The following trouble codes are usually associated with a (MAF) sensor:

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Mass Air Flow Sensor – Measures, air volume, density, temperature

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