What Does The Throttle Position Sensor Do? (1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 3.4L V6 Buick Rendezvous, Oldsmobile Alero, Silhouette)

The throttle position sensor (TPS) is a very important component of your vehicle's engine management system.

The fuel injection computer relies on it heavily to be able to efficiently and optimally manage engine operation. In this article I'll cover some of the most frequently asked questions about the TPS.

APPLIES TO: This tutorial applies to the following vehicles:

  1. 3.4L V6 Buick Rendezvous: 2002, 2003, 2004, 2005.
  2. 3.4L V6 Oldsmobile Alero: 1999, 2000, 2001, 2002, 2003, 2004.
  3. 3.4L V6 Oldsmobile Silhouette: 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004.

What Does The Throttle Position Sensor (TPS) Do?

It's the throttle position sensor's job to report the throttle plate angle to the fuel injection computer.

As you're probably already aware, the throttle plate opens and closes as you step on or step off the accelerator pedal.

In a nutshell, when the throttle plate opens, the TPS voltage signal increases. As the throttle plate starts to close, the TPS voltage signal decreases.

What Happens When The Throttle Position Sensor (TPS) Goes Bad?

For the most part, when a throttle position sensor goes bad, it will usually stay stuck producing a single voltage value as the throttle plate opens or closes.

In some cases, the throttle position sensor fails intermittently, which means that it functions perfectly most of the time but every now and then it does not produce a TPS voltage signal.

In the next section, you'll find a list of common symptoms you'll see when the TPS fails.

What Problems Can A Throttle Position Sensor (TPS) Cause?

When the throttle position sensor fails, you're going to see one or more of the following symptoms:

  • Check engine light illuminated in the instrument cluster.
  • TPS trouble codes registered in the fuel injection computer's memory:
    • Code P0121: Throttle Position Sensor Performance Problem.
    • Code P0122: Throttle Position Sensor Signal Voltage Low.
    • Code P0123: Throttle Position Sensor Signal Voltage High.
    • Code P1121: Throttle Position Sensor Intermittent High Voltage.
    • Code P1122: Throttle Position Sensor Intermittent Low Voltage.
  • Engine hesitates when you step on the accelerator pedal.
  • Lack of power when accelerating the vehicle.
  • Bad gas mileage.
  • Engine idle either too high or too low.
  • Rough engine idle.
  • The engine may start and immediately stall.
  • The engine cranks but does not start.

How Can You Tell If The Throttle Position Sensor (TPS) Is Bad?

A throttle position sensor diagnostic test is required to find out if it's bad or not.

Testing the TPS is not difficult nor a complicated thing to do. In the next section, I'll go into some of the specifics of the TPS test.

How Can I Find Out If The Throttle Position Sensor (TPS) Is Bad?

The throttle position sensor can easily be tested to find out if it's bad or not. Testing it is the surest way to find out if it is functioning correctly or not.

This is the throttle position sensor's test procedure:

  1. Checking for TPS trouble code stored in the fuel injection computer's memory.
  2. Making sure that the TPS is getting power.
  3. Making sure that the TPS is getting Ground.
  4. Making sure that the TPS signal increases/decreases as the throttle plate is opened/closed.

If the TPS has failed, its output voltage signal will not increase/decrease as you open/close the throttle plate.

You can find the throttle position sensor test explained in a step-by-step manner here: How To Test The Throttle Position Sensor (3.4L V6 Buick, Oldsmobile).

Can I Drive My Car With A Bad Throttle Position Sensor (TPS)?

In most cases, the engine performance problems caused by a bad TPS will not allow you to safely drive the vehicle.

But, even if the vehicle can be driven, you should avoid doing so.

Where Can I Buy The Throttle Position Sensor (TPS)?

The following links will help you to comparison shop for the throttle position sensor (of known professional automotive brands- NO knockoffs) for your 3.4L V6 Buick (Oldsmobile).

NOTE: All of the 3.4L V6 equipped Buick and Oldsmobile vehicles covered by this tutorial use the exact same throttle position sensor.

More 3.4L V6 Buick, Oldsmobile Tutorials

You can find a complete list of 3.4L V6 Buick (Oldsmobile) tutorials in this index:

  1. GM 3.4L Index Of Articles.

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

  1. How To Test Engine Compression Test (3.4L V6 Buick, Oldsmobile).
  2. How To Test A Blown Head Gasket (3.4L V6 Buick, Oldsmobile).
  3. What Does The CKP Sensor Do? (3.4L V6 Buick, Oldsmobile).
  4. How To Test The Throttle Position Sensor (3.4L V6 Buick, Oldsmobile).
Thank You For Your Donation

If this info saved the day, buy me a beer!

If This Info Saved the Day, Buy Me a Beer!


Buick Vehicles:

  • Rendezvous 3.4L
    • 2002, 2003, 2004, 2005

Oldsmobile Vehicles:

  • Alero 3.4L
    • 1999, 2000, 2001, 2002, 2003, 2004
  • Silhouette 3.4L
    • 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004