A mass airflow (MAF) sensor is used to measure the amount of air entering the combustion chamber and calculate the amount of fuel that will burn completely in the given amount of air.
It is mandatory for the proper functioning of the MAF sensor that each of these wires is working correctly. But the question is, how do we know whether these wires are working correctly or not?
We have the following tests to check the proper functioning of these wires. In this powerful article, you are going to learn how to test mass air flow sensors with and without a multimeter.
Related Post: Mass Air Flow Sensor (MAF): How It Works & Functions
How To Test Mass Air Flow Sensor
The MAF sensor test is very easy. All you need is to determine the wiring diagram of the MAF sensor.
The mass air flow sensor mainly consists of four types of wires namely
- Power Wire
- MAF Ground
- Voltage Signal or Frequency Signal
- Signal Ground
In this guide, we will discuss the MAF sensor test with and without a multimeter
Related Post: How To Clean Mass Air Flow (MAF) Sensor
How To Test Mass Air Flow Sensor With Multimeter
The Mass Air Flow Sensor’s Power Wire Test
- Open the hood of the car.
- Disconnect the connector of the MAF sensor.
- Set the multimeter to 20 volts.
- Connect the black lead of the multimeter to the ground terminal of the battery or chassis and the red one to the power feed terminal of the MAF connector.
- Turn the ignition of the car on.
- If you get 5 to 12 volts, then it is working correctly.
The Mass Air Flow Sensor’s Ground Wire Test
- Set the multimeter to 20 volts.
- Disconnect the connector of the MAF sensor.
- Connect the black lead of the multimeter to the ground terminal of the MAF sensor and connect the red lead to the battery positive source or the positive wire inside the MAF sensor connector.
- Turn the ignition of the car on.
- If you get 5 to 12 volts, then it is working correctly.
The Mass Air Flow Sensor’s Signal Wire Test
- Turn the ignition of the car off.
- Connect the MAF sensor to the connector.
- Connect the black lead to the negative terminal of the battery or chassis and the red lead to the signal terminal of the MAF sensor.
- Ensure that the connections are isolated and then start the vehicle.
- If the signals on the multimeter are 0.5 to 0.7 volts, then it is functioning properly.
- For further surety wiggle the connector wires, if the voltage is steady, then it is normal.
- Increase the RPMs to 2500-3500; the voltage must increase to 1.5-3.0 volts.
Related Post: Mass Air Flow (MAF) Sensor Wiring Diagram
The Mass Air Flow Sensor’s Frequency Signal Wire Test
Some mass air flow sensors send output to the ECU in voltage and some in frequency.
In this section, we will test the mass air flow sensor’s frequency signal wire.
- Turn the ignition switch off.
- Set the multimeter to a frequency scale.
- Connect the black lead of the multimeter to the negative terminal of the battery or chassis and the red lead to the signal terminal of the MAF sensor.
- After isolating the connections, start the engine.
- If the frequency of the signal terminal is around 30 hertz, then the frequency wire is working properly.
- Try wiggling the wires, if the frequency remains steady, then the wire is properly working.
- The frequency on the multimeter should increase smoothly on increasing the RPM of the car.
The Mass Air Flow Sensor’s Signal Ground Test
- Set the multimeter to 20 volts.
- Disconnect the connector of the MAF sensor.
- Connect the black lead of the multimeter to the signal ground terminal of the MAF sensor and connect the red lead to the battery positive source or the positive wire inside the MAF sensor connector.
- Turn the ignition of the car on.
- If you get 5 to 12 volts, then it is working correctly.
How To Test Mass Air Flow Sensor Without Multimeter
Testing the MAF sensor through a Digital Multimeter is the most efficient way to check the MAF sensor. But in case, the multimeter is not available, you can check the MAF sensor by observing it physically.
If the mass air flow sensor is contaminated or is choked with dust, the RPMs of the vehicle’s recorded car will be less. If in case the RPM of the vehicle recorded is more or less than the RPM of another car with a known good MAF sensor, the MAF sensor of the subject car is damaged or dirty.
Try to gently pull the wiring of the MAF sensor to know whether the wiring has any cut inside the insulator. In this way, the MAF sensor of the vehicle could be checked without a digital multimeter.
Frequently Asked Questions (FAQs)
There is no definitive answer to this question as it depends on the specific mass airflow sensor in question. However, in general, the voltage for the signal wire at the mass airflow sensor should be within the 0.5 to 0.7 volts range in order for it to function properly. If the voltage is too low, the sensor may not be able to accurately measure the airflow. If the voltage is too high, the sensor may overheat and become damaged.
The battery should be disconnected when cleaning the mass air flow sensor to avoid any potential damage to the sensor. Once you have finished cleaning the sensor, you will need to relearn the correct operating parameters for your car. When disconnecting the battery, it is important to follow the manufacturer’s instructions to ensure that the process is done safely and correctly.
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Thank you so very much was having a hard time with checking my MAF sensor your article simplified it very quickly. I have a 2004 Kia Amanti and it is very difficult to get wiring diagrams for this car .I have book to repair just numbers of where wires are located. You helped thank you. Cpt T.
CptT, My Pleasure!