what to do after replacing mass air flow sensor

Mass Air flow Sensor (MAF): how it works, symptoms, problems, testing

Updated: July 09, 2021

Mass Air menses Sensor (MAF).

The Mass Air Flow sensor (MAF) is one of the key components of an electronic fuel injection system in your car. Information technology is installed between the air filter and the intake manifold of the engine. See the diagram. The mass air menstruum sensor measures the amount of air inbound the engine or the air menstruum.
In modernistic cars, an intake air temperature or IAT sensor is built in the mass air menses sensor. At that place are few types of air flow sensors, withal, modern cars utilise a hot-wire blazon. Permit'due south see how it works.

How a hot-wire air flow sensor works

A hot-wire mass air menstruum sensor has a minor electrically heated wire (hot wire). A temperature sensor installed close to the hot wire measures the temperature of the air virtually the hot wire.

When the engine is idling, a small corporeality of air flows around the hot wire, so it takes a very low electric current to continue the wire hot.

Toyota mass air flow sensor (MAF).

When yous printing the gas, the throttle opens allowing more air to menstruation over the hot wire. The passing air cools the wire downwards. The more than air flows over the wire, the more electric current is needed to go on information technology hot. The electric current is proportional to the amount of air flow. A pocket-size electronic chip installed inside the air menses sensor translates the electric current into a digital signal and sends information technology to the engine estimator (PCM). The PCM uses the air flow betoken to summate how much fuel to inject. The goal is to proceed the air/fuel ratio at the optimal level.

In addition, the PCM uses air menstruation readings to determine the shift points of the automated transmission. If the air menses sensor doesn't work properly, the automatic manual might shift differently likewise.

Mass air menses sensor bug

Volkswagen mass airflow sensor.

Problems with mass air flow sensors are common in many cars, including BMW, GM, Volkswagen, Mazda, Toyota, Nissan and other brands. The sensor element could get contaminated or damaged.
For example, in some Mazda Skyactiv engines, a failed mass air flow sensor could crusade the engine to crank just not to offset.
An improperly installed or collapsed air filter tin crusade the air flow sensor to fail sooner. Over-soaking a washable air filter can also cause problems with the air flow sensor.

Symptoms of a bad mass air flow sensor

A contaminated or failed mass air flow sensor cannot mensurate the amount of air menstruation correctly. This causes the engine calculator to miscalculate the amount of injected fuel.

Mass Air flow Sensor (MAF).

As a result, a bad mass air menstruum sensor causes various driveability problems, including a no-start, stalling, lack of power and poor dispatch. In add-on, a faulty mass air flow sensor might cause the Cheque Engine or Service Engine Soon light to come on. A trouble with the air flow sensor could also alter the shifting pattern of the automatic transmission.

When the air flow sensor signal varies from the expected range, the PCM records a mistake and stores the corresponding trouble code, illuminating the Check Engine low-cal on the dash. This trouble code tin exist retrieved with a scan tool. The following problem codes are ordinarily associated with a mass air menstruation sensor:
P0100 - Mass Air Flow Circuit Malfunction
P0101 - Mass Air Catamenia Circuit Range/Operation
P0102 - Mass Air Flow Circuit Low
P0103 - "Mass Air Flow Circuit High"
P0104 - "Mass Air Flow Circuit Intermittent"
Problem codes P0171 Organisation Too Lean (Bank 1) and P0174 System Also Lean (Bank 2) are too often acquired by a bad or contaminated mass air flow sensor.

How the mass air flow sensor is tested

In modern cars, the simply style to test the mass air flow sensor is with a browse tool. Mechanics measure the amount of air menses (mass air flow sensor readings) at different RPMs. They compare the readings to the specifications or to the readings of a known-proficient mass airflow sensor.

Mass Airflow Sensor (MAF) readings of a ii.4L 4-cylinder engine at different RPMs.

Often mass air flow sensor readings are measured at idle, 1,000 RPM, 2,000 RPM and 3,000 RPM. A contaminated or bad air flow sensor volition, in most cases, show lower air flow readings than a known good one. In some rare cases a bad sensor may evidence higher readings. Of course, different engines will accept dissimilar readings. The air flow depends on the engine volume, so a V6 or V8 engine volition have higher readings.

Low mass air menses readings exercise non mean the sensor is bad. A chock-full upward air filter or plugged catalytic converter can likewise crusade lower air period sensor readings. Vacuum leaks bear on air flow sensor readings likewise. That's why mechanics use a known-adept sensor to compare the readings. Read more than: Vacuum leaks: common sources, symptoms, repairs.

Is there a way to check the mass air flow sensor readings at home? Of class, for example, here we used the complimentary Torque app to mensurate the mass air flow sensor readings at different RPMs (in the photo). This mass air flow sensor is good.

To apply whatever phone app that connects to your car, y'all will need a Bluetooth adaptor that plugs into the OBD connector.

Sometimes a poor electrical connexion at the air flow sensor connector could too cause the air flow readings to exist out of range. For this reason, the air menstruum sensor connector terminals likewise as the wiring needs to be carefully inspected.

Oftentimes if an air filter is not installed properly, or the air filter box is not closed, a piece of debris tin can go sucked into the mass air menstruation sensor (come across this photograph) and crusade bug. Sometimes the debris tin can autumn in during the air filter replacement. In this example, the repair is like shooting fish in a barrel. The mass air flow sensor must be cleaned and the air filter must be reinstalled correctly or replaced.

Air flow sensor replacement

If the air menstruation sensor is bad, it needs to be replaced. It'due south a fairly elementary task. The part costs from $89 to $380. If a sensor is dirty, your mechanic may suggest cleaning information technology (cleaning the airflow sensor is a delicate procedure) as a temporary solution; sometimes it could help. When replacing the mass air flow sensor, make certain the air filter is installed properly.

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Source: https://www.samarins.com/glossary/airflow_sensor.html

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