2 Ways to Test a MAF Sensor with an OBDII Scan Tool

By | March 13, 2023

2 Ways Test a MAF Sensor with a Low Cost Scan Tool
Testing a MAF (Mass Airflow Sensor) is quick and easy to do with an OBDII scan tool.

A high-end scan tool is not needed; almost any low-cost OBDII scan tool will work, including $20-$30 dollar units.

What is the MAF Sensor?

What is the MAF Sensor
The MAF (Mass Airflow Sensor) sensor measures how much airflow is going into the engine.

The sensor reports this information to the onboard computer (ECM/PCM), which uses this information to adjust the oxygen/fuel ratio mixture.

Where is the MAF Sensor Located?

Toyota MAF Sensor 3
The MAF Sensor is located on or near the air intake box.

It will be located after the air filter, usually on the air intake box or the hose attached to the engine.

Which OBDII Scan Tools Can Test a MAF Sensor?

Which OBDII Scan Tools Can Test a MAF Sensor
An OBDII scan tool that has live data or a data stream option can test a MAF sensor.

Almost all scan tools will have these options, including very low-cost units.

For example, the LAUNCH CR319 OBDII Scanner is one such low-cost unit that has the data stream option.

How Do You Test the MAF Sensor?

How Do You Test the MAF Sensor
There are two main ways to test a MAF Sensor first with a multi-meter ad second with an OBDII scan tool.

Both methods work well with it a personal choice which is best to use.

Often it depends on which tools are available, with using a scan tool is the easiest method.

The first scan tool method checks the MAF sensor using the Grams Per Second to measure airflow with the engine off.

Since the engine is off, the number should not be very high or low, or the sensor is having an issue.

The second method is done with the engine running and examining the Grams Per Second to measure airflow.

Once a basic range of the MAF sensor Grams Per Second is known, the engine RPM is doubled.

A working good MAF sensor reading should also double with the engine RPM.

If the sensor reading does not double with the RPM, then it is having an issue.

A video is at the bottom of the page for a visual walk-through if needed.

How to Test a MAF Sensor a Scan Tool Option #1

  1. Turn the key to the On Position but do Not start the engine.
  2. How to Test a MAF Sensor a Scan Tool 1

  3. Go to Live Data or Data Stream, depending on the scan tool.
  4. How to Test a MAF Sensor a Scan Tool 2

  5. Find the MAF G/S (Grams per a second) data.
  6. How to Test a MAF Sensor a Scan Tool 3

  7. Examine the Grams per a second.
  8. The number should not be too high or too low with the engine off and not running.
  9. How to Test a MAF Sensor a Scan Tool 4

  10. Since no airflow is going past the sensor, it should not be reading much, if any, airflow.

How to Test a MAF Sensor a Scan Tool Option #2

  1. Turn the key to the On Position but do Not start the engine.
  2. How to Test a MAF Sensor a Scan Tool 1

  3. Go to Live Data or Data Stream, depending on the scan tool.
  4. How to Test a MAF Sensor a Scan Tool 2

  5. Start the engine and examine the G/S (Grams per a second).
  6. How to Test a MAF Sensor a Scan Tool 3 Option 2

  7. Double the engine RPM.
  8. How to Test a MAF Sensor a Scan Tool 3 Option 3

  9. The MAF sensor G/S (Grams per a second) should also double.
  10. How to Test a MAF Sensor a Scan Tool 4

Summary
Testing a Mass Airflow Sensor is easy with an OBDII scan tool.

Almost any scan tool will work that has the Live Data or Data Stream feature.

The first method to test the sensor is to read the MAF sensor Grams per a second data with the engine off.

Since there is no air flowing pasts the sensor, the reading would be very low.

The next method is to read the Grams per a second data with the engine on.

The engine RPM is double, and the Grams per a second data should also double.

Have you had any issues testing a MAF sensor? Let us know your thoughts below.

Bob Thomas
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