How To Test The Idle Switch of the TPS (1.6L Nissan Sentra)

As you're already aware, the throttle position sensor assembly, on your 1.6L Nissan Sentra (w/ an automatic transmission) is part idle switch and part throttle position sensor (this is the reason why it has two connectors).

In this tutorial, I will show how to test the idle switch part of the throttle position sensor assembly and also how to adjust 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 1.6L Test Tutorials.

NOTE: If you need to test the throttle position sensor part of the idle switch, this tutorial will help: How To Test The TPS (1997-1999 1.6L Nissan Sentra).

En Español Puedes encontrar este tutorial en Español aquí: Cómo Probar el Interruptor de Ralentí (1997-1999 1.6L Nissan Sentra) (en: autotecnico-online.com).

Idle Switch Continuity Tests

How To Test The Idle Switch of the TPS (1.6L Nissan Sentra)

To identify the idle switch portion of the TPS assembly, it'll help you to know that the idle switch's connector is gray and the TP sensor's connector is brown. Also, the gray idle switch connector has only two wires coming out of it. The TPS sensor's brown connector has 3 wires coming out of it.

Diagnosing the idle switch (to see if its good or bad or misadjusted) simply involves testing the continuity between 2 specific pins with a multimeter in Ohms mode.

The pins we're gonna' test are labeled with the numbers 5 and 6 in the illustration in the image viewer.

Test 1 Specifications
Throttle Angle Pins Ohms
Closed Throttle 5 and 6 Continuity
Wide Open Throttle 5 and 6 No Continuity
Test 2 Specifications
Throttle Angle Pins Ohms
Closed Throttle 4 and 5 No Continuity
Wide Open Throttle 4 and 5 Continuity

If the throttle switch on your 1.6L Nissan Sentra 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 Adjust The TPS (1.6L Nissan Sentra)

The throttle position sensor assembly has to be adjusted to a specific voltage output. In this section I'll explain the adjustment procedure.

NOTE: The TP sensor assembly needs to be connected to its connectors for the multimeter voltage adjustment to take place. The continuity adjustment is done with the TP sensor assembly disconnected from its connectors. For the voltage part of the test, you'll need to use a back-probe or a wire-piercing probe. To see what a wire-piercing probe looks like, go here: Wire Piercing Probe.

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: .35 to .65 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.
  7. As a last check, disconnect the TPS assembly from its connectors and check that:
    1. Idle switch pins 5 and 6 have continuity only with the throttle plate closed.
    2. Idle switch pins 4 and 5 have continuity only with the throttle plate in its wide open position.

Where To Buy The TPS And Save

Nissan parts are expensive, if you buy them at your local auto parts. Check out the following links. I think they'll save you a few bucks:

Not sure if the above TPS fits your particular 1.6L Nissan? Don't worry, once you get to the site they'll make it fits by asking you the specifics of your particular Nissan vehicle. If it doesn't fit, they'll find you the right one.

More 1.6L Nissan Tutorials

You can find a complete list of tutorials in this index: Nissan 1.6L Index of Articles.

Here's a small sample of the 1.6L Nissan tutorials you'll find in the index:

  1. How To Test Engine Compression (1.6L Nissan).
  2. How To Test The TPS (1997-1999 1.6L Nissan Sentra).
  3. Mass Air Flow (MAF) Sensor Test Nissan Sentra 1.6L (1995-1999) (at: easyautodiagnostics.com).