How To Test The Idle Switch (Nissan 3.3L)

The idle switch on your 3.3L Nissan Pathfinder (Frontier, Xterra, QX4) is part of the throttle position sensor assembly and can be easily tested with a simple multimeter resistance test.

In this tutorial, I'm gonna' show you how to test it and how to adjust it (if you need to replace it).

Here are the contents of this tutorial at a glance:

  1. Idle Switch Continuity Tests.
  2. Adjusting The Throttle Position Sensor Assembly.
  3. Where To Buy Your TP Sensor And Save.
  4. More Nissan 3.3L Test Tutorials.

If you need to test the throttle position sensor part of the idle switch, this tutorial will help: Throttle Position Sensor Test (Nissan 3.3L Pathfinder, Xterra, Frontier).

En Español Puedes encontrar este tutorial en Español aquí: Cómo Probar el Interruptor de Ralentí (Nissan 3.3L Pathfinder, Xterra, Frontier) (en: autotecnico-online.com).

Idle Switch Continuity Tests

How To Test The Idle Switch (Nissan 3.3L)

Testing the idle switch involves measuring continuity between specific pins of the throttle position sensor assembly.

Since the TP sensor assembly is 2 sensors in 1 and has two connectors.... the pins that we're going to be testing are the ones that the gray connector connects to and these are labeled with the numbers 4, 5 and 6 in the illustration in the image viewer.

The bottom brown connector connects to the TP sensor part and supplies it with power, ground, and relays the throttle angle voltage signal to the PCM.

Idle Switch Closed Throttle Specifications
Throttle Angle Pins Ohms
Closed Throttle 5 and 6 No Continuity
Open Throttle 5 and 6 No Continuity
Idle Switch Open Throttle Specifications
Throttle Angle Pins Ohms
Closed Throttle 4 and 5 Continuity
Open Throttle 4 and 5 No Continuity

If the throttle switch on your Nissan Pathfinder (Xterra, Frontier, QX4) doesn't pass any of the above pin continuity tests... then, before replacing it, you need to make sure that it's not misadjusted. The next subheading will help you with this procedure.

Adjusting The Throttle Position Sensor Assembly

How To Test The Idle Switch (Nissan 3.3L)

If you need to remove and replace the throttle position sensor assembly... you'll need to adjust it to the correct specification before you bolt it down.

This is a pretty easy adjustment and in this section I'll show you how to do it.

NOTE: The TP sensor assembly needs to be connected to its connectors for this adjustment to take place.

This is what you'll need to do:

  1. Turn the ignition switch to its Off position and make sure the TP sensor assembly is connected to its connectors.
  2. Turn the ignition switch to its On position but don't start the engine.
  3. Place your multimeter in Volts DC mode and:
    1. Connect the red multimeter lead to the wire that connects to the pin labeled with the number 2 (see the illustration in the image viewer above).
    2. Ground the black multimeter lead on the battery negative terminal.
    3. NOTE: Remember the throttle position sensor assembly must remain connected to its connectors through the entire adjustment.
  4. Adjust the TPS sensor by rotating it until the output voltage is within specification:
    1. Specification: .3 to .7 volts DC.
  5. Once the output voltage has reached the above voltage specification, tighten the TP sensor assembly mounting bolts.
  6. Once you're done, recheck the output voltage to make sure the TP sensor didn't move on you when you tightened the two bolts.

Where To Buy Your TP Sensor And Save

Just recently one of my cousins needed to buy a TP sensor for her 1998 Nissan Pathfinder and I was shocked and how much paid for it at our local auto parts store! After all, the TP sensor she bought is a no-name brand Chinese knockoff that she paid over $100 (US) for.

I didn't have the heart to tell her that she could've bought it a whole lot cheaper online, but I will tell you and I'll show you where to buy it. You can buy it here:

Not sure the TP sensor listed fits your particular Nissan? Don't worry, they'll make sure it fits your Nissan, once you get to the TP sensor site, or they'll find the right one for you.

More Nissan 3.3L Test Tutorials

If this tutorial was helpful/informative, you can find a complete list of tutorials here: Nissan 3.3L Index of Articles.

Here's a sample of the tutorials you'll find there:

  1. How To Troubleshoot A No Start (Nissan 3.0L, 3.3L, 3.5L).
  2. How To Test Engine Compression (Nissan 3.0L, 3.3L, 3.5L).
  3. Mass Air Flow (MAF) Sensor Test 3.3L Frontier, Quest, Pathfinder, XTerra (at: easyautodiagnostics.com).
  4. How To Bench Test A Starter Motor (Step by Step) (at: easyautodiagnostics.com).