How To Test The Throttle Position Sensor (1996-1998 1.6L Sidekick)

The throttle position sensor assembly, on your 1.6L Suzuki Sidekick (1.6L Geo Tracker or 1.6L Chevy Tracker) is 2 sensors in one. One part of the assembly is the throttle position sensor and the other is an idle switch.

In this tutorial I'm gonna' teach you how to test the throttle position part of the TPS assembly, to see if it's bad or not, using a simple multimeter. That's right, no scan tool needed!

APPLIES TO: This tutorial applies to the following vehicles:

• 1.6L Chevrolet Tracker: 1998.
• 1.6L Geo Tracker: 1997.
• 1.6L Suzuki Sidekick: 1996, 1997, 1998.

MAF SENSOR DIAGNOSTIC TESTS:

• How To Test The MAF Sensor (1992-1998 1.6L Sidekick).

Symptoms Of A Bad Throttle Position Sensor

The throttle position part of the TPS assembly on your 1.6L Sidekick (Tracker) tracks the movement of the throttle plate and reports it to the PCM.

This is due to the fact that the throttle plate is connected to the accelerator pedal via the accelerator cable. So when you step on or off the accelerator pedal, the accelerator cable actuates the throttle plate to open or close.

As you're already aware, more air enters the engine as you step on the accelerator pedal and the throttle plate opens. As you let off of the accelerator pedal, the throttle plate closes and admits less air into the engine.

The info the TPS provides the PCM helps it to calculate engine load and either inject more or less fuel. This makes it one very important sensor! So, when it fails, your 1.6L Sidekick's engine performance is gonna' take a major hit!

When the TPS fails, you'll also see one or more of the following symptoms:

1. Check engine light (CEL) illuminated on your 1.6L Sidekick's instrument panel.
2. A TPS diagnostic trouble code (DTC) stored in the PCM's memory:
   • P0121: Throttle Position Sensor Circuit Performance.
   • P0122: Throttle Position Sensor Signal Voltage Low.
   • P0123: Throttle Position Sensor Signal Voltage High.
3. Your 1.6L Sidekick's fails the smog check (state mandated emissions test).
4. Bad gas mileage.
5. Hard start and/or extended cranking time (after shut off).
6. Black smoke coming out of the tailpipe.
7. Hesitation when accelerating your vehicle down the road.

Thankfully, the TPS can be tested without a scan tool and in the next section we'll start with the very first test.

Where To Buy Your TP Sensor And Save

Buying your 2.5L Suzuki 1.6L Sidekick's TPS online is your best bet at saving some bucks. The following links will help you shop and compare:

Not sure if the above TP sensor fits your particular 1.6L Sidekick? 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.

TEST 1: Testing The Throttle Position Sensor Voltage Signal

As mentioned earlier, the TPS's job is to report the throttle plate angle to the PCM as you step on or off the accelerator pedal.

The throttle plate angle signal that the TPS creates is a Volts DC signal that you and I can see with a simple multimeter.

Reading the TPS voltage signal is done by tapping into the TPS signal wire with the multimeter in its Volts DC mode and then manually actuating the throttle plate to see the changes in the TPS voltage signal being read by the multimeter.

The TPS wire that we need to tap into is the gray (GRY) wire of the 4-wire TPS engine wiring harness connector.

If you don't have a multimeter and need to buy one, this is the one I use and recommend: Tekpower TP8268 AC/DC Auto/Manual Range Digital Multimeter (Amazon affiliate link).

NOTE: The throttle position sensor has to remain connected to its connector for this test to work (this is where a wire piercing probe comes in handy to get to the signal inside the wire. To see what one looks like, go here here: Goupchn 4mm Banana to Banana Plug Test Leads Kit (Amazon affiliate link).

OK, let's start:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   With the red multimeter test lead probe the GRY wire of the sensor's connector.
   
   The GRY wire is the one that connects to TPS pin #3 in the illustration above.

3. 3

   Ground the black multimeter test lead on the battery negative (-) terminal.

4. 4

   Have your helper turn the key to the ON position, but don't start the engine (this will power up the TP sensor).

5. 5

   Your multimeter should report a voltage between 0.2 to 0.9 Volts DC. If your multimeter doesn't, don't worry about it just yet, continue with the other steps.

Part 2

1. 6

   Slowly open the throttle plate (by hand and from the engine compartment) while you observe the change in voltage numbers on your multimeter.
   
   For this test result to be accurate, you need to open the throttle plate by hand from the engine compartment and not from inside the vehicle.

2. 7

   As the throttle plate opens, the voltage numbers will increase.
   
   This increase in voltage should be smooth and without any gaps or skips.
   
   Once the throttle plate is wide open, your multimeter should read somewhere between 3.5 to 4.5 Volts DC.

3. 8

   Slowly close the throttle plate.
   
   As the throttle plate is closing, you should see the voltage decrease smoothly and without any gaps or skips, to the exact same voltage you noticed in step 5.

Part 3

1. 9

   Lightly tap on the throttle position sensor with the handle of a screw-driver (or something similar, and I want to emphasize the words ‘lightly tap’) as you slowly open and close the throttle plate and observe the multimeter.
   
   If the TPS is bad, the tapping will cause the voltage numbers to skip or go blank. If the TPS is OK, the tapping will have no effect on the voltage numbers.

2. 10

   Repeat step 9 several times to make sure of your multimeter test results.

Let's take a look at your test results:

CASE 1: The throttle angle voltage increased and decreased as you opened and closed the throttle plate. This test result confirms that the TP sensor is OK and not defective.

I suggest one more check, and this is to see if the TPS is adjusted correctly. For this adjustment check, go to: How To Adjust The 1.6L Sidekick TPS.

CASE 2: The throttle angle voltage DID NOT increase (and/or decrease) as you opened and closed the throttle plate. This test result confirms that the TPS is behind the TPS trouble code lighting up the check engine light (CEL) on your 1.6L Sidekick (Tracker).

I'm gonna' suggest that you make sure that the TP sensor is getting both power and Ground by performing the last two tests in this tutorial. To check that the TPS is getting power, go to: TEST 2: Verifying Throttle Position Sensor Has Power.

CASE 3: The multimeter DID NOT register any voltage. This test result doesn't condemn the TP sensor as bad just yet. Why? Because the TP sensor may be missing either power or Ground.

So the next step is to check that the TP sensor is getting power, go to: TEST 2: Verifying Throttle Position Sensor Has Power.

TEST 2: Verifying Throttle Position Sensor Has Power

One of the things that can stop the TPS from creating a voltage signal is if the sensor is not getting power.

So, if your TPS did not pass TEST 1, then before we condemn the TPS as bad, we need to check that the gray with red stripe (GRY/RED) wire of the TPS connector is feeding the sensor with 5 Volts DC.

We'll do a simple multimeter voltage test to confirm that these 5 Volts are indeed present.

OK, these are the test steps:

1. 1

   Place your multimeter's dial in Volts DC mode and turn the key on but don't start the engine.
   
   This will power up the TP sensor's connector.

2. 2

   Disconnect the TPS from its electrical connector.

3. 3

   Probe the GRY/RED wire of the TPS connector with the red multimeter test lead. The GRY/RED wire connects to TPS pin #4 in the illustration above.
   
   IMPORTANT Use a back probe or a wire piercing probe instead of probing the front of the TPS electrical connector.

4. 4

   Connect the black multimeter test lead to the negative (-) battery terminal.

5. 5

   When you've set up the test, have a helper turn the key to the ON position but don't crank or start the engine.

6. 6

   Your multimeter should display 4.5 to 5 Volts on its screen if the GRY/RED wire has power.

Let's take a look at your test results:

CASE 1: The GRY/RED wire, of the TPS connector, has 4.5 to 5 Volts. So far so good since this tells you that the throttle position sensor (TPS) is getting power from the fuel injection computer.

The next and last test, is to make sure that the throttle position sensor is getting Ground (from the PCM too). For this test, go to: TEST 3: Verifying Throttle Position Sensor Has Ground.

CASE 2: The GRY/RED wire, of the TPS connector, DOES NOT have 4.5 to 5 Volts. Double check all of your connections and repeat the test.

If your multimeter still doesn't register the 4.5 to 5 Volts DC, then this test result tells you that the TPS itself is not at fault (and thus causing the TPS trouble code). Without power, the TPS can't create a throttle angle voltage signal. Although beyond the scope of this tutorial, your next step is to diagnose and restore this missing power.

TEST 3: Verifying Throttle Position Sensor Has Ground

So far, your diagnostic tests have confirmed several things:

• You have a TPS trouble code lighting up the check engine light on your Sidekick.
• The TPS's throttle plate position voltage signal IS NOT increasing/decreasing as you manually open/close the throttle plate (TEST 1).
• The TPS is getting power on the GRY/RED wire of its electrical connector (TEST 2).

The next step is to see if the grey with yellow stripe (GRY/YEL) wire of the TPS connector is feeding Ground to the TPS. We'll check for this Ground by doing a multimeter voltage test.

IMPORTANT: Ground is provided directly by the fuel injection computer. Be careful and don't intentionally or accidentally short this wire (circuit) to battery power or you'll fry the fuel injection computer.

OK, here are the test steps:

1. 1

   Set your multimeter to Volts DC mode.

   
   
2. 2

   Disconnect the TPS from its electrical connector.

3. 3

   Probe the GRY/YEL wire of the TPS connector. The GRY/YEL wire connects to TPS pin #1 (see illustration above).
   
   NOTE: Be careful not to damage the terminal if you probe it on the front of the connector. If possible, you should use a back probe or a wire-piercing probe to check this circuit.

4. 4

   Connect the red multimeter test lead to the battery positive (+) terminal.

5. 5

   Turn the key to its ON position but don't start the engine. This will power up the fuel injection computer.

6. 6

   Your multimeter will display 10 to 12 Volts if terminal #1 is feeding the TPS with Ground.

   
   

Let's see what your test result means:

CASE 1: The GRY/YEL wire is feeding the TPS Ground. This is the correct and expected test result. Now, if you arrived to this test conclusion by starting out with TEST 1, then you can conclude that the TP sensor is bad and needs to be replaced.

To explain why (you need to replace the TPS): Up to this point, you have verified:

1. The TP sensor's voltage signal DOES NOT increase/decrease when you manually opened/closed the throttle plate.
2. The TP sensor is being fed 5 Volts DC.
3. The TP sensor is being fed Ground.

So, taking all of these test results together you can conclude the TPS is bad and needs to be replaced.

CASE 2: The GRY/YEL wire IS NOT feeding the TPS Ground. Check your test connections once more and repeat the test. If your multimeter still does not register 12 Volts, then you can conclude that:

1. The TPS itself is NOT bad.
2. There's an open in the wire between the TP sensor harness connector and the fuel injection computer's harness connector.
3. The fuel injection computer has an internal problem (although this is extremely rare).

Although testing these two conditions are beyond the scope of this article, you have now eliminated the throttle position sensor (TPS) on your 1.6L Sidekick (1.6L Tracker) as being the cause of the problem and/or the TP sensor diagnostic trouble code (DTC) lighting up the check engine light (CEL).

How To Adjust The 1.6L Sidekick TPS

The Suzuki manual calls for the TPS to be adjusted when removed. So in this section, I'll explain the adjustment procedure below:

1. Disconnect the negative battery terminal from the battery.
2. Loosen the throttle position sensor screws.
3. Place a 0.026" (0.65mm) feeler gauge between the throttle lever and throttle lever stop screw.
4. Place your multimeter in Ohms mode.
5. Check the resistance between TPS pin #1 and pin #2. Continuity must exist between these two pins while the feeler gauge is inserted between the throttle lever and the throttle lever stop screw.
6. If continuity does not exist between pin #1 and #2, rotate the TPS assembly till it does and then tighten the TPS screws.
7. After tightening the TPS screws, re-check that continuity still exists between pin #1 and #2 (with the feeler gauge still inserted).

More 1.6L Sidekick Diagnostic Tutorials

You can find a complete list of 1.6L Suzuki Sidekick diagnostic tutorials in this index:

• Suzuki 1.6L Index of Articles

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

• How To Test For A Blown Head Gasket (1.6L Suzuki Sidekick, Geo Tracker).
• How To Test The MAF Sensor (1992-1998 1.6L Sidekick).
• Oxygen Sensor Heater Test -P0141 (1996-1998 1.6L Suzuki Sidekick).
• How To Test The Engine Compression (1.6L Suzuki Sidekick, Geo Tracker).