Maf Scan Tool Readings for Mass Air Flow Sensor
Mass Air flow Sensor (MAF): how it works, symptoms, issues, testing
Updated: July 09, 2021
Mass Air menses Sensor (MAF).
The Mass Air Menses sensor (MAF) is 1 of the cardinal components of an electronic fuel injection organization in your car. It is installed betwixt the air filter and the intake manifold of the engine. See the diagram. The mass air flow sensor measures the amount of air entering the engine or the air flow.
In modern cars, an intake air temperature or IAT sensor is congenital in the mass air catamenia sensor. There are few types of air flow sensors, however, modern cars use a hot-wire type. Let'southward encounter how it works.
How a hot-wire air flow sensor works
A hot-wire mass air menstruation sensor has a modest electrically heated wire (hot wire). A temperature sensor installed close to the hot wire measures the temperature of the air most the hot wire.
When the engine is idling, a pocket-size amount of air flows around the hot wire, and then it takes a very low electric current to go along the wire hot.
Toyota mass air catamenia sensor (MAF).
When you lot press the gas, the throttle opens allowing more than air to menses over the hot wire. The passing air cools the wire down. The more air flows over the wire, the more electrical electric current is needed to continue information technology hot. The current is proportional to the corporeality of air flow. A small electronic chip installed inside the air flow sensor translates the electric current into a digital signal and sends it to the engine reckoner (PCM). The PCM uses the air menstruation signal to calculate how much fuel to inject. The goal is to keep the air/fuel ratio at the optimal level.
In add-on, the PCM uses air catamenia readings to determine the shift points of the automated transmission. If the air flow sensor doesn't work properly, the automated manual might shift differently also.
Mass air flow sensor problems
Volkswagen mass airflow sensor.
Issues with mass air flow sensors are common in many cars, including BMW, GM, Volkswagen, Mazda, Toyota, Nissan and other brands. The sensor element could become contaminated or damaged.
For example, in some Mazda Skyactiv engines, a failed mass air catamenia sensor could cause the engine to creepo but not to beginning.
An improperly installed or collapsed air filter can cause the air flow sensor to neglect sooner. Over-soaking a washable air filter can also crusade problems with the air flow sensor.
Symptoms of a bad mass air menstruation sensor
A contaminated or failed mass air flow sensor cannot measure the amount of air flow correctly. This causes the engine computer to miscalculate the amount of injected fuel.
Mass Air period Sensor (MAF).
As a effect, a bad mass air flow sensor causes various driveability bug, including a no-beginning, stalling, lack of power and poor acceleration. In addition, a faulty mass air flow sensor might cause the Bank check Engine or Service Engine Soon light to come on. A problem with the air period sensor could likewise alter the shifting design of the automatic transmission.
When the air catamenia sensor indicate varies from the expected range, the PCM records a mistake and stores the corresponding trouble code, illuminating the Cheque Engine low-cal on the nuance. This problem lawmaking can exist retrieved with a scan tool. The following trouble codes are commonly associated with a mass air flow sensor:
P0100 - Mass Air Flow Excursion Malfunction
P0101 - Mass Air Flow Excursion Range/Performance
P0102 - Mass Air Menses Circuit Low
P0103 - "Mass Air Flow Circuit High"
P0104 - "Mass Air Flow Excursion Intermittent"
Problem codes P0171 System Too Lean (Banking concern ane) and P0174 Arrangement Too Lean (Banking company ii) are also often caused past a bad or contaminated mass air flow sensor.
How the mass air period sensor is tested
In mod cars, the only fashion to examination the mass air flow sensor is with a scan tool. Mechanics mensurate the amount of air flow (mass air menstruation sensor readings) at different RPMs. They compare the readings to the specifications or to the readings of a known-expert mass airflow sensor.
Mass Airflow Sensor (MAF) readings of a two.4L 4-cylinder engine at different RPMs.
Often mass air flow sensor readings are measured at idle, one,000 RPM, two,000 RPM and 3,000 RPM. A contaminated or bad air period sensor will, in most cases, show lower air catamenia readings than a known good ane. In some rare cases a bad sensor may show college readings. Of class, different engines will take dissimilar readings. The air menstruation depends on the engine volume, so a V6 or V8 engine will have higher readings.
Depression mass air flow readings do not mean the sensor is bad. A chock-full upwardly air filter or plugged catalytic converter can too cause lower air flow sensor readings. Vacuum leaks impact air period sensor readings too. That's why mechanics employ a known-skilful sensor to compare the readings. Read more: Vacuum leaks: common sources, symptoms, repairs.
Is there a way to check the mass air flow sensor readings at abode? Of course, for example, here we used the gratuitous Torque app to measure the mass air menses sensor readings at different RPMs (in the photo). This mass air menses sensor is good.
To apply whatsoever phone app that connects to your machine, you will demand a Bluetooth adaptor that plugs into the OBD connector.
Sometimes a poor electrical connection at the air menses sensor connector could also cause the air menstruation readings to exist out of range. For this reason, the air flow sensor connector terminals as well every bit the wiring needs to be carefully inspected.
Often if an air filter is not installed properly, or the air filter box is not closed, a piece of debris tin go sucked into the mass air catamenia sensor (see this photo) and cause problems. Sometimes the debris can fall in during the air filter replacement. In this case, the repair is easy. The mass air flow sensor must be cleaned and the air filter must exist reinstalled correctly or replaced.
Air menstruum sensor replacement
If the air flow sensor is bad, it needs to exist replaced. It'due south a fairly elementary job. The office costs from $89 to $380. If a sensor is muddy, your mechanic may suggest cleaning information technology (cleaning the airflow sensor is a frail procedure) every bit a temporary solution; sometimes it could assistance. When replacing the mass air catamenia sensor, make sure the air filter is installed properly.
Maf Scan Tool Readings for Mass Air Flow Sensor
Source: https://www.samarins.com/glossary/airflow_sensor.html