How To Test a Nissan Sentra MAF Sensor

How To Test a Nissan Sentra MAF Sensor

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When your Nissan Sentra MAF Sensor begins to fail over time, it can cause your 2.0 liter Sentra to run poorly. MAF stands for the Mass Air Flow sensor, and it’s primary role is to read and analyze the air that’s rushing into your engine. The MAF informs your Sentra ECU about the air temperature, how much air and other important information.

When this sensor begins to fail or becomes faulty, there’s quite a few problems that can arise. Most of these can be seen through OBDII trouble codes or fault codes that can cause your Sentra to run poorly or cause starting problems.

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Today I’ll be showing you how to test the MAF in a 2008 Nissan Sentra with a 2.0 liter engine in it. The mass air flow sensor is located in the intake tract of the engine, and is connected to a six pin weatherproof connector.

If you own a 1.6 liter equipped Nissan Sentra, check the MAF testing How To guide here.

Symptoms of a bad Nissan Sentra MAF Sensor

When your MAF sensor begins to go bad, the check engine trouble code light may light on your dash. Some of these trouble codes can range from P0101, P0102, or P0103. If you see your check engine light turn on, you can use a scan tool to retrieve the codes stored in your Nissan ECU.

These trouble codes can cause your Sentra to run overly rich or lean, depending on what’s wrong. These problems can create poor fuel economy or even engine damage under extreme circumstances.

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Our test vehicle has a P0102 trouble code, and because it’s a 2008 Nissan Sentra we will be showing you how to test the MAF directly. The specific verbiage for this trouble code is Mass Air Flow Circuit Low Input so part of our how to will show you how to measure the signal wire.

How does the Nissan Sentra MAF Sensor Work?

This sensor is secured to the mass air flow housing using two bolts. This housing is secured inline with your air intake tract for your 2.0 liter engine. This sensor measures the intake flow rate and converts it to a voltage that your ECU can read.

Your Nissan Sentra MAF Sensor uses a hot wire system to read the temperature of incoming airflow. The heat generated by the hot wire is reduced as the intake air flows around it.

If your Sentra has a OBDII trouble code for MAF signal low, this means that the hotwire sensor is going bad. We’ll be starting our how-to guide by testing the MAF sensor for power first.

How to Test your Nissan Sentra MAF Sensor

The first part of testing your MAF sensor is to check your mass air flow sensor for power. To do this insert your ignition key and turn to the “ON” position but do not turn the engine on. Now open your Sentra hood and locate your MAF sensor, which is mounted inline of the MAF housing.

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Unplug the MAF connector and you will be testing your MAF harness for power. This harness is a six pin weatherproof connector, and you will be using a multimeter to start the testing procedure.

If you are not sure of what a multimeter is, check our handy guide here to learn how to use one. Once you have a firm grasp of what you are doing, turn the dial of your multimeter to DC mode and put the black lead to your negative terminal. Now gently probe PIN 5 of your MAF connector to see if there’s a power signal.

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The wiring diagram of the Nissan Sentra MAF sensor is above, make sure you are testing PIN 5 of the wiring connector side. This is represented as PIN 2 if you are facing the front of the connector counting the pins from left to right.

There should be 5 volts of power here at this pin, remember do not force the multimeter probe into the harness. Gently probe PIN 5 for power and if you have it, this means your MAF is getting the right amount of voltage. Next probe PIN 2 which is the power wire for your intake air temperature sensor. There should also be 5 volts of power here at this pin, and if you have power at both pins your MAF should be powered and operational.

Testing your Nissan Sentra MAF Sensor signal

If you have power at both of these wires, the next step is to backpin your MAF connector. This can be done using a paper clip that’s opened up and bent so that one end can be gently inserted into the back of the MAF connector. The signal wire for your 2.0 liter 2008 Nissan Sentra is PIN 3. You can also check the MAF signal at PIN 58 of your Nissan Sentra ECU as well.

Now plugin your MAF connector back into the sensor, and insert the backpin paperclip into PIN 3. Using your multimeter you will now begin reading the signal voltage being sent from the MAF to your ECU. Again, if this is too hard you can always test from your ECU harness, the PIN in question is PIN 58.

Keep your hands and clothing free of your engine and any moving parts, and start the engine. Once it’s warmed up, you will read the voltage from PIN 3 of your Nissan Sentra MAF Sensor. The voltage at idle should be 0.9-1.1 volts and this is the easiest reading to gather.

The next setting to check would have a friend sit in the car and rev the car to 2,500 RPM. This should be done with zero load on the engine, and your transmission in PARK or neutral. Your MAF sensor reading should be 1.4 volts – 1.7 volts at the signal wire. If you have a low MAF sensor trouble code, this is where most of your low voltage issues will arise.

If your Nissan Sentra MAF Sensor spits out a reading at the signal wire that’s outside of these specifications, replace your mass air flow sensor. Use a scan tool to reset your Nissan ECU and clear your trouble code.

Have any questions about our How to DIY guide? Leave us a comment below and let us know!

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