TEST 2: Testing The Resistance Between Terminals D And E (TPS 1)
In this test section, we're gonna' test the continuity of terminals D and E while we manually open the throttle plate.
Terminal D is the one that outputs the TPS 1 signal to the fuel injection computer. Terminal E is the terminal that gets 5 Volts from the fuel injection computer.
As we slowly open the throttle plate, your multimeter's resistance readings should increase smoothly and without gaps in the reading.
As you slowly close the throttle plate, the resistance reading should decrease back to the original resistance value you observed at the start.
NOTE 1: All multimeter connections are done on the male spade terminals of the electronic throttle body itself.
NOTE 2: To make it easier to connect your multimeter test leads to the throttle body's terminals (and open the throttle plate), I recommend that you use insulated alligator terminals on the ends of your multimeter test leads.
These are the test steps:
- 1
Disconnect the throttle body from its electrical connector.
- 2
Place your multimeter in Ohms mode.
- 3
Connect the red multimeter test lead to terminal D and the other test lead to terminal E.
At this point I usually see an Ohms reading of about 2.7 K Ohms from a good TPS 1. - 4
Slowly open the throttle plate by hand till it reaches its wide open throttle (WOT) position.
The resistance value should increase smoothly and without any gaps as you open the throttle plate.
At this point I usually get a reading of about 3.3 K Ohms from a good TPS 1. - 5
Slowly release the throttle plate.
The resistance value should decrease smoothly and without any gaps as you close the throttle plate.
With the throttle plate pushed down and completely closed, I usually see a reading of about 2.1 K Ohms in a good TPS 1.
Let's examine your test results:
CASE 1: The resistance increased and decreased without any gaps as you opened and closed the throttle plate. This is the correct test result.
If your 3.5L Chevrolet Malibu's electronic throttle body passed TEST 1 and TEST 2, then you can conclude that TPS 1 (inside the electronic throttle body) is OK and not defective.
The next step is to test TPS 2. For the first test of two, go to: TEST 3: Testing The Resistance Between Terminals E And F (TPS 2).
CASE 2: The resistance DID NOT increase nor decrease as you opened and closed the throttle plate. This lets you know that TPS 1 is bad. You'll need to replace the throttle actuator assembly.
CASE 3: The resistance increased and decreased BUT with gaps in the reading as you opened and closed the throttle plate. This lets you know that TPS 1 is bad. You'll need to replace the throttle actuator assembly.
TEST 3: Testing The Resistance Between Terminals E And F (TPS 2)
We're gonna' test the resistance of terminals E and F while we manually open and close the throttle plate.
As you're already aware from the previous tests, terminal E is the terminal that gets 5 Volts from your 3.5L Chevy Malibu or Pontiac G6's fuel injection computer.
Terminal F is the terminal that outputs the signal that TPS 2 creates to your Malibu or G6's fuel injection computer.
As we open the throttle plate, the resistance value should decrease and as we close it, the resistance value should increase.
NOTE: All multimeter connections are done on the male spade terminals of the electronic throttle body itself.
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 E and the other multimeter test lead to terminal F.
At this point I have usually gotten a resistance reading of about 2.2 K Ohms from a good TPS 2. - 4
Slowly open the throttle plate by hand till it reaches it wide open throttle (WOT) position.
The resistance value should decrease smoothly and without gaps as you completely open the throttle plate.
I have usually gotten an Ohms reading of about 1.2 K Ohms at WOT from a good TPS 2 at this point. - 5
Slowly release the throttle plate and push down on the throttle plate so that it completely closes.
The resistance value should increase smoothly and without any gaps as you close the throttle plate.
With the throttle plate pushed down and completely closed I usually see a reading of about 2.4 K Ohms at this point.
Let's examine your test results:
CASE 1: The resistance decreased and increased without gaps in the reading as you opened and closed the throttle plate. This is the correct test result.
If your 3.5L Chevrolet Malibu's electronic throttle body passed TEST 1, TEST 2, and TEST 3 then you can conclude that TPS 1 and TPS 2 (inside the electronic throttle body) are OK and are not defective.
The next step is to test the TAC motor (that's also located inside the electronic assembly). For the first test go to: TEST 4: Testing The TAC Motor.
CASE 2: The resistance DID NOT decrease nor increase as you opened and closed the throttle plate. This lets you know that TPS 2 is bad. You'll need to replace the throttle actuator assembly.
CASE 3: The resistance decreased and increased BUT with gaps in the reading as you opened and closed the throttle plate. This lets you know that TPS 2 is bad. You'll need to replace the throttle actuator assembly.
