Mass Air Flow (MAF) Sensor Test 3.0L Nissan Maxima (1995-1999)

TEST 2: Making Sure The MAF Sensor Is Getting Ground

The next step, after confirming that the MAF sensor on your Nissan Maxima is getting power, is to check that it also has a good path to Ground.

Without a good path to Ground, the mass air flow (MAF) sensor can't produce a MAF voltage signal.

The circuit (wire) that provides this path to Ground is the wire labeled with the number 2.

Let's get started:

1. 1

   Turn key to the OFF Position and place your multimeter in Volts DC mode.

2. 2

   Disconnect the MAF sensor from its connector.

3. 3

   Connect the black multimeter test lead to the MAF sensor wire identified with the number 2 in the photo.
   
   Use a back probe or a wire piercing probe to check the wire.

4. 4

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

5. 5

   Your multimeter should register 10 to 12 Volts if Ground is present.

Let's interpret your multimeter test result:

CASE 1: Your multimeter registered 10 to 12 Volts. This result indicates that the Maxima's MAF sensor has a good Ground circuit. The next step is to test the MAF signal, go to: TEST 3: Testing The MAF Signal With A Multimeter.

CASE 2: Your multimeter DID NOT register 10 to 12 Volts. Verify that all of your multimeter connections are connected securely and try the test again. If still no voltage, then this result exonerates the Maxima's MAF sensor as the cause of the MAF code lighting up your check engine light (CEL) or MAF issue, since without this Ground, the MAF sensor will not produce a signal to the computer.

Finding and repairing the cause of this missing Ground will resolve the MAF sensor issue with your Nissan Maxima.

TEST 3: Testing The MAF Signal With A Multimeter

OK, now for the test you signed up for! We're gonna' test the mass air flow sensor's output signal with a multimeter.

We're gonna' connect the multimeter to the MAF sensor's signal wire and see if it increases/decreases as we rev up/rev down the engine.

If the MAF sensor is defective, the MAF signal will stay stuck in one voltage value when you rev up the engine.

It's important that the Maxima's engine be at its normal operating temperature for this test, so start the engine and let it warm up.

IMPORTANT: The MAF sensor must be connected to its connector to perform this test. To access the MAF signal in the wire, you'll need to use a back-probe on the connector or a wire piercing probe on the wire. To see an example of this tool and where to buy it, go here: Wire-Piercing Probe.

These are the test steps:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Probe the MAF sensor wire that is identified with the number 1 in the photo with the red multimeter test lead.

3. 3

   Ground the black lead at the battery negative (-) terminal.

4. 4

   Crank and start the already warmed up engine.

5. 5

   Note the Volts DC reading on your multimeter as the engine idles.
   
   This reading may fluctuate a bit, but no matter what the instability in the reading, this will be your base voltage reading.

6. 6

   Manually accelerate the engine. The voltage reading on your multimeter should increase.

7. 7

   Let the engine return to idle. The voltage value on the multimeter should return to the base voltage value you recorded in step 5.
   
   This voltage reading may not be the exact same but should be very close.

8. 8

   Repeat this as often as you need to verify that the voltage value increases/decreases when you accelerate/decelerate the engine.

Let's interpret your multimeter test result:

CASE 1: The voltage reading increased and decreased smoothly according to the amount of acceleration you caused, then the Maxima's MAF sensor is working correctly.

CASE 2: The voltage reading DID NOT increase and decrease smoothly according to the amount you accelerated or decelerated the engine, then the mass air flow sensor on your Nissan Maxima is bad. Replace the MAF sensor.