How To Test The Electronic Throttle Body (2004-2007 V8 Chevrolet Express, GMC Savana)

By: Abraham Torres-Arredondo
Created: 27 March 2024
Updated: 27 March 2024
Articl Id: 1158

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TEST 2: Testing TPS 2 With A Multimeter

Testing TPS 2 With A Multimeter (Part 2 Of 2). How To Test The Electronic Throttle Body (2004, 2004, 2005, 2006, 2007 Chevrolet Express, GMC Savana)

In this test section, we'll test the resistance between terminal E and terminal F as we open/close the throttle plate.

If everything's okay with the circuit, the resistance should decrease as you open the throttle plate, and it should increase as you close the throttle plate.

If there's a problem with this circuit, you'll see the resistance value stuck in one value, or gaps in the reading as you open/close the throttle plate.

Let's get started:

1
Disconnect the throttle body from its electrical connector.
2
Place your multimeter in Ohms mode.
3
Connect one multimeter test lead to male terminal B.

NOTE: All connections are done on the male spade terminals of the connector of the throttle body itself.
4
Connect the other multimeter test lead to male terminal D.
5
The multimeter should show around 4 K Ohms Ω.
6
Slowly open the throttle plate by hand till it reaches its wide-open throttle (WOT) position.
7
The multimeter should show the resistance decreasing as you open the throttle plate.

NOTE: The multimeter's needle should move smoothly and steadily across the scale as you open the throttle plate.
8
Slowly close the throttle plate to its closed position.
9
The resistance value should increase

NOTE: The multimeter's needle should move smoothly and steadily across the scale as you close the throttle plate.
10
Gently push down and completely close the throttle plate.
11
The resistance value should continue to decrease as you completely close the throttle plate.

Let's examine your test results:

CASE 1: The multimeter's needle moved smoothly and steadily across the scale without any drops as you opened/closed the throttle plate. This is the correct test result and it lets you know that TPS 2 is OK (not defective).

The next and last test is to test the throttle plate actuator motor. For this test go to: TEST 3: Testing The TAC Motor.

CASE 2: The multimeter's needle DID NOT move across the scale as you opened/closed the throttle plate. This lets you know that TPS 2 is bad. You'll need to replace the throttle body unit.

CASE 3: The multimeter's needle moved across the scale but dropped (jumped) as you opened/closed the throttle plate. This lets you know that TPS 2 is bad. You'll need to replace the throttle body unit.

TEST 3: Testing The TAC Motor

Testing The TAC Motor. How To Test The Electronic Throttle Body (2004, 2004, 2005, 2006, 2007 Chevrolet Express, GMC Savana)

For our last test, we'll test the throttle actuator motor to see if it has suffered an open-circuit or a short-circuit problem.

If the throttle actuator motor is OK, you should see a resistance reading between 2 and 13 Ohms.

Any Ohms reading below 1 Ohm indicates that the throttle actuator motor has suffered a short-circuit internally.

If your multimeter indicates a reading of no continuity, then the throttle actuator motor has suffered an internal open-circuit problem.

These are the test steps:

1
Disconnect the throttle body from its electrical connector.
2
Place your multimeter in Ohms mode.
3
Connect one multimeter test lead to terminal A and the other to terminal C.
4
Your multimeter should read continuity.

If the resistance reading is below 1 Ohm, then the motor has an internal short-circuit problem.

If the resistance reading is in the K Ohms range or your multimeter reads OL, then the motor has an internal open-circuit problem.

The resistance reading I've gotten from good throttle actuator motors has been between 2 and 12 Ohms.

Let's examine your test results:

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

You can conclude that the electronic throttle body is working correctly (and not the problem) if you have:

Confirmed that the resistance of the TPS 1 circuit decreases/increases as you open/close the throttle plate (TEST 1).
Confirmed that the resistance of the TPS 2 circuit decreases/increases as you open/close the throttle plate (TEST 2).
Confirmed that the TAC motor has not suffered an open-circuit or short-circuit issue (this test section).

CASE 2: The multimeter registered 0 Ohms between terminal A and C (or a value very close to it). This lets you know that the TAC motor has an internal short-circuit problem and is defective.

Replace the throttle actuator assembly.

CASE 3: The multimeter reports no continuity between terminal A and C (the letters OL are displayed). This lets you know that the TAC motor has an internal open-circuit problem and is defective.

Replace the throttle actuator assembly.