How To Test The Idle Switch (1996-1999 3.0L Maxima)

The throttle position sensor assembly, on your 3.0L Nissan Maxima, is two components in one. One part of the TPS assembly is the idle switch and the other is the actual throttle position sensor.

Testing and/or adjusting the idle switch assembly can easily be done with a multimeter and this is the focus of this tutorial.

NOTE: If you need to test the throttle position sensor part of the idle switch, this tutorial will help: How To Test The Throttle Position Sensor (1996-1999 3.0L Maxima).

You can find this tutorial in Spanish here: Cómo Probar El Interruptor de Ralentí (1996-1999 3.0L Maxima) (at: autotecnico-online.com).

Idle Switch Continuity Tests

The idle switch's job is to tell the PCM when the throttle plate is in its 'closed throttle' position and when it's in its 'wide open' throttle position. How? By closing one set of circuits while another set is open inside the idle switch.

This means that you and I can easily test the actual performance of the idle switch by checking for continuity (with a multimeter) between two specific pins when the idles switch is in its wide open throttle (WOT) position and closed throttle position.

Now, since the throttle position sensor assembly, on your 1996-1999 3.0L Nissan Maxima, has two connectors (a brown one and a gray one). You need to know that:

• The brown wiring harness connector connects to the throttle position sensor portion of the TPS assembly.
• The gray one connects to the idle switch portion of the TPS assembly.

Using the illustration above, the throttle position sensor assembly pins we're gonna' test are labeled with the numbers 5 and 6.

NOTE: The multimeter continuity tests are done on the idle switch (portion of the TPS assembly) terminals and not on the gray connector.

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

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

If the throttle switch on your Nissan Maxima 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

The throttle position sensor assembly needs to be adjusted after replacement or if the continuity of the closed and open throttle circuits of the idle switch are not within specification. Thankfully, the adjustment is very straight forward and easy process.

NOTE: The TP sensor assembly needs to be connected to its connectors for this adjustment to take place in steps 1 through 6.

This is what you'll need to do to adjust the TPS assembly:

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:
   • Connect the red multimeter test lead to the wire that connects to the pin labeled with the number 2 (see the illustration in the image viewer above).
   • Ground the black multimeter test lead on the battery negative (-) terminal.
4. Adjust the TPS sensor by rotating it until the output voltage is within specification:
   • Specification: 0.3 to 0.7 Volts DC.
5. Once the output voltage has reached the above voltage specification, tighten the TP sensor assembly mounting bolts.
6. Recheck the output voltage to make sure the TP sensor didn't move on you when you tightened the two bolts.
7. Now, disconnect the TPS from its two connectors and with your multimeter in Ohms mode check that:
   • Idle switch pins 5 and 6 have continuity at closed throttle plate position.
   • Idle switch pins 4 and 5 have continuity at wide open throttle plate position.
8. If both the voltage spec and the continuity specs are present, the TPS assembly is correctly adjusted.

Where To Buy Your TP Sensor And Save

Where can you buy the TP sensor for your 3.0L Nissan? You can buy it at your local auto parts store, but it's gonna' cost a whole lot more. I suggest taking a look at the price of the TP sensor in the following links and compare:

Not sure if the above TP sensor fits your particular 3.0L Nissan? Don't worry, once you get to the site, they'll make sure it fits by asking you the particulars of your vehicle. If it doesn't fit, they'll find you the right one.

More 3.0L Nissan Tutorials

You can find a complete list of tutorials in this index: Nissan 3.0L Index Of Articles.

Here's a small sample of the 3.0L Nissan tutorials, you'll find in the index:

• Mass Air Flow (MAF) Sensor Test 3.0L Nissan Quest (1993, 1994, 1995).
• Mass Air Flow (MAF) Sensor Test 3.0L Nissan Maxima (1995-1999).
• How To Test The Starter Motor (Nissan 3.0L, 3.3L) (at: troubleshootmyvehicle.com).
• How To Test Engine Compression (Nissan 3.0L, 3.3L, 3.5L) (at: troubleshootmyvehicle.com).