Nissan Pathfinder P0101 Trouble Code – Test your MAF Sensor

When you have a Nissan Pathfinder P0101 OBDII trouble code, it’s a sign that your mass air flow sensor is not working correctly. When your Pathfinder check engine light turns on, your 3.5 liter Nissan will begin to run poorly. Today I’ll be showing you how to test your Nissan mass air flow sensor in a 2001 Pathfinder with a 3.5 liter engine in it. In order to test your MAF sensor and complete this OBDII DIY tutorial, you will need to use a digital multimeter.

The mass air flow sensor in your Nissan Pathfinder is responsible for reading and analyzing the incoming air stream. Your MAF sensor will then send this information to your Nissan Engine Computer Unit or ECU. The ECU uses this data to properly deliver the right amount of fuel, and using other engine inputs knows exactly when to fire the spark plugs to ensure efficient operation.

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The specific trouble code language for this check engine light is Mass Air Flow Circuit Range/Performance. This means that while your mass air flow sensor seems to be working and sending the right signals, the voltage signal being transmitted is far outside what the ECU is expecting. This indicates that your Nissan MAF sensor is either fouled or there’s an issue with your wiring.

Common Symptoms of Nissan Pathfinder P0101 trouble code

When this check engine code rears it’s ugly head, it’s going to cause serious problems with your 3.5 liter Pathfinder. Least of all you won’t be able to pass smog but in some extreme cases you won’t be able to even start your engine. Here are some other symptoms of the Nissan Pathfinder P0101 check engine code.

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  • Bad fuel economy
  • Sluggish engine response
  • Inconsistent performance
  • Engine will not start
  • Misfire
  • Check Engine Light ON

Testing your Nissan Pathfinder mass air flow sensor for signal

Because the Nissan Pathfinder P0101 trouble code typically means that your MAF sensor is working, we won’t be spending much time testing for power and ground. However if you want to test those while you are at it, it definitely doesn’t hurt matters. You will need to turn the knob on your multimeter to DC voltage, and then put the black lead or probe to the negative terminal of your battery. Now you will test the A wire for a power signal from your Nissan Pathfinder engine harness. Next test PIN B for the ground signal. If you have both, which you should, it’s time to measure the signal from your MAF sensor to fix your P0101 check engine code.

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Now to test the signal wire, you will need to reconnect your mass air flow sensor. With your Nissan Pathfinder MAF reconnected, you will pierce PIN D with your multimeter to measure the signal being transmitted by your MAF. This part of our test can be dangerous, so make sure to keep clear of your 3.5 liter engine, the drive belts and most of all your cooling fans. Now start your engine and allow it to warm up, and it’s at this point you can measure the MAF signal to see if your mass air flow sensor is acting right.

Once your engine has warmed up and you have PIN D pierced with your multimeter, you can now test the voltage range of your mass air flow sensor. With your 3.5 liter engine at idle, your Nissan mass air flow sensor should rear around 1.0 to 1.2 volts of signal. Keep in mind these voltages are not exact, and will definitely vary depending on your Nissan truck, but it should be around this value.

Now make sure the Pathfinder is in NEUTRAL or the transmission is in PARK and your parking brake is fully engaged. Now have a friend increase your engine RPM to 3000 RPM. While your friend holds the RPM at this signal, your MAF signal should read around 2.5 to 2.7 volts. Slowly allow the engine RPM to fall and your voltage should lower evenly and uniformly with no voltage spikes or odd gaps in voltage.

If you have power and ground at the pins we’ve specified in this Nissan Pathfinder Mass air flow sensor wiring schematic and your signal voltage seems iffy, it’s time for a replacement MAF sensor. Do you have a 3.5 liter Nissan engine with a persistent P0101 trouble code? If your Pathfinder falls between the year range of 2001 and above, and your P0101 trouble code isn’t going away, try checking out the Nissan factory service bulletin number NTB12-051d. Keep in mind this TSB is for a ECU reprogramming to eliminate faulty check engine lights. If you have a Nissan Pathfinder P0101 and there’s driveability issues, this service bulletin is not for you.

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