A mass air flow (MAF) sensor is one of the main components of an electric fuel injection system in a car. Basically, it is installed between the intake manifold and the air filter of the engine.

This component will measure the amount of air flow going to the engine. Modern cars have built an intake air temperature (IAT) sensor inside the mass air flow sensor. The IAT sensor used in modern cars is a hot-wire type.

The Problem With Mass Air Flow Sensors

Many cars tend to have problems with mass air flow sensors because the element could get damaged or contaminated. A faulty MAF sensor can cause the engine to crank but not to start.

On the other hand, a collapsed or improperly installed filter can cause the failure of the air flow sensor. Likewise, a washable air filter can also cause problems to its air flow sensor when over soaked.

A Bad Mass Air Flow Sensor

It will be impossible to properly measure the amount of air flow if the MAF sensor is contaminated or faulty. As a result, the engine’s computer will miscalculate the amount of injected fuel causing a number of issues.

  • Drivability problems
  • No-start issues
  • Stalling
  • Lack of power
  • Poor acceleration
  • ‘Check Engine’ or ‘Service Engine Soon’ error
  • Alter the shifting pattern of automatic transmission

Testing the Mass Air Flow Sensor

Modern vehicles can use a scan tool to test the mass air flow sensor. A mechanic will be able to measure the amount of MAF sensor readings at various RPMs. The readings will be compared to the specifications or to a good air flow sensor.

  • Testing the MAF sensor readings at different RPMs

You have to measure the MAF sensor readings at idle, 1,000 RPM, 2,000 RPM, and 3,000 RPM. Basically, a lower air flow reading is a case for a bad or contaminated air flow sensor.

However, there will be variable readings for different engine volumes. Air flow will depend on the type of engine. So, a V6 or V8 engine will have higher readings compared to smaller ones.

  • Using a known-good sensor for comparison

The condition of the sensor might not indicate that the sensor is bad. Sometimes, a plugged catalytic converter or a clogged-up air filter can also cause lower air flow readings.

Additionally, vacuum leaks can affect sensor readings. So, in order to determine a good air flow, mechanics would use a known-good sensor to compare readings.

  • Free Torque app

You can also check for MAF sensor readings at home using the free Torque app. Simply install a phone app that will connect to your car using a Bluetooth adaptor to plug into the OBD connector.

At times, the air flow sensor connector can cause the readings to fall out of range due to poor electrical connection. Thus, it is best to check the wiring and the air flow sensor terminals.

Improperly installed air filter, clogged-up sensor, or opened air filter box can cause issues. Therefore, you simply have to clean the MAF sensor and reinstall the air filter correctly.