How To Test The Throttle Position Sensor (2002-2005 GM 2.2L)

TEST 2: Verifying Throttle Position Sensor Has 5 Volts And Ground

Like any electrical component on your car, the throttle position sensor needs power (5 Volts DC) and Ground to function. So, in this test section we are going to find out if both are present by doing another simple multimeter voltage test.

So far, you have confirmed that:

• A TPS diagnostic trouble code (DTC) is lighting up the check engine light.
• The TP sensor did not pass TEST 1 because it's voltage signal IS NOT increasing/decreasing as you open/close the throttle plate.

In case you're wondering where power and Ground comes from, the are both supplied by your vehicle's fuel injection computer.

IMPORTANT: Be careful and don't short this wire to battery voltage (12 Volts) or you'll fry the PCM.

With your multimeter in Volts DC mode, this is what you need to do:

1. 1

   Verify that the wire labeled with the #1 (in the photo) has 4.5 to 5 Volts with the key on but engine off.
   
   Connect the red multimeter test lead (using the appropriate tool) to the wire labeled with the #1. Connect the black multimeter test lead to the negative (-) battery terminal.
   
   Your multimeter should read 4.5 to 5 Volts DC.

2. 2

   Verify that the wire labeled with the #2 (in the photo) has Ground with the key on but engine off.
   
   Connect the black multimeter test lead (using the appropriate tool) to the wire that connects to the wire labeled with the #2 of the TPS connector. Connect the red multimeter test lead to the positive (+) battery terminal.
   
   Your multimeter should read 10 to 12 Volts DC.

Let's take a look at what your test results mean:

CASE 1: Power and Ground are present. This is the correct and expected test result.

You can conclude that the TPS is bad only if all tests have confirmed that:

1. The TP sensor IS NOT providing a varying voltage signal when manually opening/closing the throttle plate.
2. The TP sensor is being fed 5 Volts DC.
3. The TP sensor is being fed Ground.

CASE 2: Power or Ground are not present. Double check your connections and make sure that you're testing the correct wires.

If your multimeter still does not show power and/or Ground, then you can conclude that there's an open in the wiring between the TP sensor harness connector and the PCM's harness connector. In the extreme of cases, the PCM has an internal problem (although this is very rare).

Although testing these two conditions are beyond the scope of this article, you have now eliminated the throttle position sensor (TPS) on your, 2.2L Ecotec equipped GM vehicle, as being the cause of the problem and/or the TP sensor diagnostic trouble code (DTC) lighting up the check engine light (CEL).

Where To Buy The TPS And Save

The following links will help you to comparison shop for the TPS. I think they'll save you a few bucks:

Not sure if the above TPS fits your particular 2.2L Ecotec equipped GM vehicle? Don't worry, once you get to the site they'll make sure it fits by asking you the specifics of your particular GM vehicle. If it doesn't fit, they'll find you the right one.