The pressure sensor in your 3.3 liter Nissan is also known as the barometric sensor. When this Pathfinder MAP Sensor fails on you, chances are you are going to know right away. This sensor provides a pressure signal to your Nissan Engine Control Unit, or ECU. Without this signal your Pathfinder will run rough and could run lean or with not enough fuel.
Today I’ll be showing you how to test a Pathfinder MAP Sensor in a 2000 Nissan with a 3.3 liter V6 in it. The tools you need to service your manifold pressure sensor include a digital multimeter and a Phillips screwdriver. You’ll be using the multimeter to measure the signal at the sensor and the three pin engine harness.
There’s a few things to keep in mind when testing the MAP engine harness. Because these are female terminals, never force or shove the multimeter leads into the wiring connector. Doing so can damage the metal pins inside the connector, or cause intermittent issues with your pressure sensor.
Testing the Pathfinder MAP Sensor for Power
You’ll need to test the MAP sensor for power, and to do this you’ll need to open your hood and locate the sensor first. Once you’ve found it disconnect the wiring harness and reference the Pathfinder MAP Sensor wiring diagram below. Keep in mind that the schematic below is the SENSOR side of the harness, and for testing power you are checking the ENGINE harness.
The power wire for this sensor is PIN C, and to test this wire you need to turn your Pathfinder ignition to the “ON” position. Now put the black lead to your negative terminal of your battery, and gently probe the front of PIN C with the red lead.
With the key at the “ON” position this wire should read between 4.5 and 5 volts of DC power. Once you’ve tested for power the next step is to test for a ground signal. This is PIN A on the ENGINE harness side of the MAP sensor.
If this wire returns a low reference ground signal, this means that your MAP sensor is powered up from your ECU. The last step of this DIY Test a Pathfinder MAP Sensor tutorial is measuring for the signal wire.
Testing the Pathfinder MAP Sensor Signal
This signal for your MAP Sensor in your 3.3 liter V6 Pathfinder is sent through the wire that leads to PIN B. To complete this part of this tutorial, you’ll need to reconnect the MAP sensor. Leave your ignition key at the “ON” position and reconnect the MAP sensor.
Using your multimeter lead, pierce the middle wire or PIN B. With the engine turned off and zero pressure at the sensor inlet, this wire should read between 3.2 to 4.8 volts of DC signal. To test this unit you can purchase or rent a hand vacuum, and apply vacuum at the MAP sensor inlet.
Apply 8 inches of Hg vacuum to the inlet, and the sensor wire should now read between 1.0 – 1.4 volts of DC power. Slowly let this vacuum out, and measure the signal wire and make sure the voltage slowly and evenly rises. Make sure there are no gaps in the signal or spikes as you release vacuum.
If your Pathfinder MAP Sensor doesn’t respond within these guidelines, you need a replacement sensor. Have any questions about this guide? leave them for us below.
