How To Test a Nissan Pathfinder TPS Sensor

The throttle position sensor in your Nissan is also known as the Pathfinder TPS Sensor. This sensor works as a potentiometer and its connected to the throttle shaft in your throttle body assembly. When the 3.5 liter throttle body opens to allow more air into the engine, the throttle sensor reads how far the throttle is opening. The sensor converts this position and sends the signal to your Nissan engine computer.

Your TPS sensor is much like the other Nissan units in this year range. Using two three pin connectors one drives the idle switch and the other is responsible for reading the throttle angle. Today I’ll be showing you how to test the Pathfinder TPS sensor in a 2001 Nissan truck.

Your 3.5 liter Nissan computer reads this signal and uses it to control the fuel delivery curve to your engine. When your Pathfinder TPS Sensor goes bad it’s going to cause problems with your Nissan’s EFI system. If the throttle sensor goes out, you will notice any number of the more common Nissan Pathfinder issues listed below.

Failed Pathfinder TPS Sensor Symptoms

When the 3.5 liter V6 engine in your Nissan lacks the right TPS signal, you’ll notice quite a few Nissan Pathfinder problems. Here are just a few below :

• Bad throttle response
• Inconsistent engine idle
• Engine speed increasing by itself
• Check Engine Light ON

When your Pathfinder check engine light is on for a failed TPS sensor, you’ll need a proper OBDII scan tool to check the stored code. One of the more common codes is P0120 which is a Nissan specific code for Throttle Position Sensor Signal Range/Performance.

In order to test your Pathfinder TPS sensor, you’ll need a digital multimeter. If you aren’t familiar with what this tool is, or what a voltmeter is check out our guide here. To kick off this DIY article, we’ll be checking the Pathfinder TPS sensor for power first.

Testing the Pathfinder TPS Sensor for Power

Sharing the same dual connector layout as the Frontier and Xterra of this year range, the Pathfinder TPS uses a brown connector and a gray one. The gray three pin connector is for your idle switch, and the brown three pin connector is the throttle sensor.

To begin checking this sensor connector for power and ground, turn your Nissan key to the “ON” position. With your ignition at this position your engine sensors will be receiving power and ground. Now locate your TPS sensor and disconnect the brown plug. To make things easier you can remove the 3.5 liter engine cover by removing the 10mm nuts.

The Pathfinder TPS sensor in your 3.5 liter engine is comprised of three pins. Switched power, ground and the signal wire. You’ll be testing for power first by putting the black multimeter lead to the negative battery terminal.

When testing for power never use the ground wires in your engine harness. Shorting the ground in your Nissan wiring harness can lead to your ECU blowing out and no longer functioning.

With the Pathfinder TPS sensor disconnected, the wire you will be checking is the one that leads to PIN C. Refer to our Pathfinder TPS sensor wiring diagram below to check which wire that is.

With the ignition turned to the “ON” position this wire should ready around 5 volts of power. Now that you’ve checked for power here at this wire the next one to check is the ground circuit.

The wire that leads to PIN A is usually a black wire, and that’s the ground circuit. Testing the ground here is easy to do. Simply switch the red lead to the positive battery terminal and then probe the front of WIRE A with the black lead. You should see around 12 volts of signal, which means the ground is intact in your Pathfinder TPS sensor wiring. The last part of this tutorial, I will be showing you how to measure the throttle signal. This is the same procedure you will take when you install a replacement TPS sensor and calibrate it.

Testing the Pathfinder TPS Sensor Signal

Now plug your throttle sensor back in to check the sensor signal. With this brown connector plugged back in, you will be piercing the wire that leads to PIN B with the red multimeter lead.

You should see around .4 to .9 Volts of DC signal when you have the red lead to WIRE B. Now have a friend hop into your Nissan truck and push all the way down on your gas pedal. The signal from your TPS should now read between 3.7 to 4.9 Volts DC signal.

Slowly let off the gas pedal and monitor the signal voltage. Make sure there’s no gaps in the voltage and that the signal sweeps smoothly between both closed position and Wide Open Throttle.

If the throttle sensor in your 3.5 liter Nissan does not respond in this manner, your Pathfinder TPS sensor has gone bad. Remove the twin pronged TPS and install a replacement throttle position sensor. You will then need to use your OBDII scan tool to erase your Pathfinder check engine code.

Have any questions about our Nissan Pathfinder TPS sensor? Leave us a comment below and let us know!