Mass Airflow Sensor Problems
Posted on December 31, 2019
Almost all modern cars come with an electronic fuel injection system, which is comprised of a variety of complex components. One such critical component is the Mass Air Flow Sensor (MAF). Installed between the intake manifold and the air filter of the engine, the mass airflow sensor’s job is to measure the airflow (the amount of air entering the engine).
The airflow sensors you find in modern cars have built-in Intake Air Temperature sensors (IAT). While there are different types of airflow sensors, most cars today come fitted with the hot-wire type. Let’s find out how it works.
How a Hot-Wire Mass Air Flow Sensor Works
A hot-wire mass airflow sensor basically consists of a small electrically heated wire, and a temperature sensor, which measures the temperature of the air surrounding the wire. When the engine is on idle, the amount of cool air flowing around the hot wire is low, which means a low amount of electrical current is required to keep the wire hot. However, when the gas pedal is pressed, the amount of airflow over the hot wear increases, and more current is required to keep the wire hot. The amount of airflow is proportional to the electric current.
The airflow sensor also houses an electronic chip that converts the electric current into a digital signal and delivers it to the PCM (the engine’s computer). Using the signals, the PCM then calculates the optimal amount of fuel to be injected. The main objective is to keep the fuel/air ratio at the ideal level.
Furthermore, the PCM determines the shift points in an automatic transmission based on the signals it gets from the airflow sensor. If the sensor develops an issue, it’s likely to impact the automatic transmission as well.
Common MAF Issues
MAF sensor problems are prevalent in many cars, including Volkswagen, GM, BMW, Nissan, Toyota and Mazda, to name a few. In many cases, a malfunctioning mass airflow sensor causes the engine to crank but not start.
A collapsed or an incorrectly installed air filter can lead to an airflow sensor failing prematurely. Other causes of airflow sensor trouble include over-soaking a washable air filter.
Signs of a Faulty Mass Airflow Sensor
Some common symptoms of a failing mass airflow sensor include:
Author: XBTMOM
Previous: How to Find a Reliable Mechanic Near You
How a Hot-Wire Mass Air Flow Sensor Works
A hot-wire mass airflow sensor basically consists of a small electrically heated wire, and a temperature sensor, which measures the temperature of the air surrounding the wire. When the engine is on idle, the amount of cool air flowing around the hot wire is low, which means a low amount of electrical current is required to keep the wire hot. However, when the gas pedal is pressed, the amount of airflow over the hot wear increases, and more current is required to keep the wire hot. The amount of airflow is proportional to the electric current.
The airflow sensor also houses an electronic chip that converts the electric current into a digital signal and delivers it to the PCM (the engine’s computer). Using the signals, the PCM then calculates the optimal amount of fuel to be injected. The main objective is to keep the fuel/air ratio at the ideal level.
Furthermore, the PCM determines the shift points in an automatic transmission based on the signals it gets from the airflow sensor. If the sensor develops an issue, it’s likely to impact the automatic transmission as well.
Common MAF Issues
MAF sensor problems are prevalent in many cars, including Volkswagen, GM, BMW, Nissan, Toyota and Mazda, to name a few. In many cases, a malfunctioning mass airflow sensor causes the engine to crank but not start.
A collapsed or an incorrectly installed air filter can lead to an airflow sensor failing prematurely. Other causes of airflow sensor trouble include over-soaking a washable air filter.
Signs of a Faulty Mass Airflow Sensor
Some common symptoms of a failing mass airflow sensor include:
- Failure to start
- Stalling
- Poor acceleration
- An altered shifting pattern (automatic transmission only)
- Irregular power delivery
- Check Engine or Service Engine light coming on.
Author: XBTMOM
Previous: How to Find a Reliable Mechanic Near You