Electronic Throttle Body Tests (2005-2006 2.2L Chevrolet Cobalt)

Testing the electronic throttle body, on the 2005-2006 2.2L Chevrolet Cobalt, to find out if it's bad or not is not difficult.

You're gonna' be surprised how easy it is to test it and in this tutorial, I'll explain how to do it in a step-by-step way.

NOTE: This tutorial applies to the 2005-2006 2.2L Chevrolet Cobalt only.

You can find this tutorial in Spanish here: Cómo Probar El Cuerpo Del Acelerador Electrónico (2005-2006 2.2L Chevrolet Cobalt) (at: autotecnico-online.com).

NOTE: You can find the TAC system wiring diagram here: TAC System Wiring Diagram (2005-2009 2.2L Chevrolet Cobalt).

Symptoms Of A Bad Electronic Throttle Body

The electronic throttle body, on your 2005-2006 2.2L Chevy Cobalt, is a very critical part of the engine management system. When it fails, you're gonna' see one or more of the following symptoms:

• The check light engine light will be lit up by one of the following trouble codes:
  • P0121: Throttle Position Sensor (TPS) Sensor 1 Performance.
  • P0122: Throttle Position Sensor (TPS) Sensor 1 Circuit Low Voltage.
  • P0123: Throttle Position Sensor (TPS) Sensor 1 Circuit High Voltage.
  • P0222: Throttle Position Sensor (TPS) Sensor 2 Circuit Low Voltage.
  • P0223: Throttle Position Sensor (TPS) Sensor 2 Circuit High Voltage.
  • P2135: Throttle Position Sensor (TPS) Sensor 1 And 2 Correlation.
• Your 2.2L Chevy Cobalt will run in Reduced Engine Power mode.
• The engine starts and runs but when you try to accelerate your Chevy Cobalt, it accelerates very slowly.
• The engine starts and runs but the engine does not accelerate when you step on the accelerator pedal.
• The engine starts and runs but shuts down.

Electronic Throttle Body Terminal Pin Out Chart

The electronic throttle body is made up of 3 electrical components. These are: throttle position sensor (TPS) 1, throttle position sensor (TPS) 2, and the throttle actuator motor.

Because of these 3 components, the throttle body's electrical connector has a total of 8 wires coming out of it. Here's a brief description of each:

Pin	Wire Color	Description
A	DK GRN	TPS 1 Signal
B	TAN/WHT	Ground (TPS 2)
C	GRY	5 Volts (TPS 1)
D	PPL	TPS 2 Signal
E	BRN	Throttle Actuator Motor Control
F	YEL	Throttle Actuator Motor Control
G	TAN	Ground (TPS 1)
H	LT BLU/BLK	5 Volts (TPS 2)

The connector on the throttle body itself has male spade terminals. The terminals on the electrical connector has female terminals.

All of the tests in this tutorial are done on the connector of the throttle body itself and this connector has male spade terminals.

Where To Buy The Electronic Throttle Body And Save

The following links will help you comparison shop for the electronic throttle body for the 2005-2006 2.2L Chevrolet Cobalt:

Not sure if the electronic throttle body will fit your particular GM vehicle? Don't worry, once you get to the site, they'll make sure it fits. If it doesn't, they'll find you the right one.

TEST 1: TPS 1 Resistance Test (Part 1 Of 2)

We're gonna' start off by testing the resistance between terminal C and terminal G of the throttle body's connector. Both of these terminals belong to TPS 1 circuit within the electronic throttle body.

Terminal C is the terminal that receives 5 Volts from your Chevy Cobalt's fuel injection computer. Terminal G is the one that receives Ground from the fuel injection computer.

The best way to connect your multimeter to the male terminals on the connector is by using jumper wires with alligator clips (see the photo at the beginning of this tutorial).

NOTE: All multimeter connections are done on the male spade terminals of the electronic throttle body itself.

These are the test steps:

1. 1

   Disconnect the throttle body from its electrical connector.

2. 2

   Place your multimeter in Ohms mode.

3. 3

   Connect the red multimeter test lead to terminal C.

4. 4

   Connect the black multimeter test lead to terminal G.

5. 5

   Your multimeter should read continuity.
   
   At this point I have gotten about 3.5 K Ohms from a good TPS 1.

Let's examine your test results:

CASE 1: The multimeter registered continuity between terminals C and G. This is the correct test result.

The next test is to check TPS 1 while we manually open and close the throttle plate. For this test go to: TEST 2: TPS 1 Resistance Test (Part 2 Of 2).

CASE 2: The multimeter DID NOT register continuity between terminals C and G. This lets you know that TPS 1 or TPS 2 is bad. With this test result you can conclude that the electronic throttle body is defective and needs to be replaced.