MAF SENSOR TEST 1: Verifying The MAF Sensor Is Getting Power

Making Sure The MAF Sensor Is Getting Power. How To Test The 2000-2002 Nissan Sentra 1.8L MAF Sensor

The very first thing you'll do, is test to make sure the MAF sensor on your 1.8L Nissan Sentra is getting power.

You can accomplish this test by using either a multimeter or a 12 Volt automotive test light, altho' the testing instructions assume you're using a multimeter.

You can check for this voltage with the MAF connected to its connector or not, the important thing to remember, if you do this test with it disconnected is NOT to probe the front of the connector. Probing the front of the connector will damage the metal female terminals.

These are the steps:

  1. 1

    Probe the wire that's labeled with the number 4 in the photo.

    To avoid probing the front of the terminal/connector, my suggestion is to use an appropriate tool to pierce the wire and then connect the red multimeter test lead to it.

  2. 2

    Ground the black multimeter test lead. For the best result, connect it on the battery negative (-) terminal.

  3. 3

    Now, turn the Key to the On position but do not crank or start your Nissan Sentra.

  4. 4

    With the multimeter in Volts DC mode, it should register about 11 to 12 Volts DC.

Let's find out what your test result means:

CASE 1: The multimeter registered 12 Volts: this result confirms the MAF sensor on your Nissan Sentra is being fed with power. The next step is to check the Ground circuit. Go to: MAF SENSOR TEST 2: Verifying The MAF sensor Is Getting Ground.

CASE 2: Multimeter DID NOT register 12 Volts: Recheck all of your test connections and repeat the test. If still no voltage, then this result exonarates the MAF sensor since without power, it's not gonna' work.

Finding the source/cause of this missing voltage will get your MAF sensor back to functioning.

Altho' it's beyond the scope of this article to test for this missing voltage, the most common cause for this condition is one of two things: An open-circuit problem in the wire between the sensor and the computer, or a bad computer. You have at least eliminated the MAF sensor itself as the cause of the problem.

MAF SENSOR TEST 2: Verifying The MAF Sensor Is Getting Ground

Making Sure The MAF Sensor Is Getting Ground. How To Test The 2000-2002 Nissan Sentra 1.8L MAF Sensor

In the previous test we checked that the sensor was receiving 12 Volts. Now we'll check that the MAF sensor is getting a good Ground. This Ground is provided by the fuel injection computer internally.

Be careful and take extreme care not to short-circuit this wire to Ground or power as you're probing it (or you'll fry the computer).

This wire (circuit) can also be tested with the connector connected to mass air flow (MAF) sensor or not.

This is what you'll need to do:

  1. 1

    Probe the wire that's labeled with the number 3 in the photo with the black multimeter test lead.

  2. 2

    Connect the red multimeter test lead to the battery positive (+) terminal.

  3. 3

    Now, turn the Key to the On position but do not crank or start your Nissan Sentra.

  4. 4

    Your multimeter (in Volts DC mode) should register about 11 to 12 Volts DC.

Let's take a look at what your test result means:

CASE 1: The multimeter registered 12 Volts: this result confirms the fuel injection computer is providing a path to Groud. The next step is to check the 5 Volt Reference circuit. Go to: MAF SENSOR TEST 3: Verifying The 5 Volt Reference Voltage.

CASE 2: Multimeter DID NOT register 12 Volts: Recheck all of your test connections and repeat the test. If still no voltage, then this result exonarates the MAF sensor since without a path to Ground, it's not gonna' work.

Finding the source/cause of the lack of Ground will get your MAF sensor back to functioning.

Altho' it's beyond the scope of this article to test for this missing Ground, the most common cause for this condition is one of two things: An open-circuit problem in the wire between the sensor and the computer, or a bad computer. You have at least eliminated the MAF sensor itself as the cause of the problem.