TEST 2: APP Sensor 1 Resistance Tests (2 Of 2)
In this test section we're going to test the resistance between terminal D and terminal E as you depress and release your Chevy TrailBlazer or GMC Envoy's accelerator pedal.
If APP sensor 1 is working correctly you're going to see that the resistance value decreases as you depress the pedal. And the resistance value will increase when you release the accelerator pedal.
If APP sensor 1 is defective you're going to see that the resistance value will stay stuck in one number as you depressed and release the accelerator pedal.
Or you're going to see that the resistance reading on your multimeter has big gaps as you depress and release the accelerator pedal.
These are the test steps:
- 1
Disconnect the APP sensor assembly from its electrical connector.
- 2
Place your multimeter in Ohms mode.
- 3
Connect one multimeter test lead to terminal D and the other test lead to terminal E.
At this point I generally see a resistance reading of about 3 K Ohms from a good APP sensor 1. - 4
Slowly depress the pedal by hand till it bottoms out.
The resistance value should decrease
With the pedal fully depressed I generally see a resistance reading of about 500 Ohms (0.5 K Ohms) from a good APP sensor 1. - 5
Slowly release the accelerator pedal.
The resistance value should increase back to the value (or close to it) that you saw in step 3.
Let's examine your test results:
CASE 1: The resistance decreased/increased smoothly and without gaps as you depressed/released the accelerator pedal. This is the correct test result. If APP sensor 1 passed TEST 1, then you can conclude that APP sensor 1 is working correctly (not defective).
The next step is to test APP sensor 2. Go to: TEST 3: APP Sensor 2 Resistance Tests (1 Of 2).
CASE 2: The resistance DID NOT decrease/increase as you depressed/released the accelerator pedal. This test result lets you know that APP sensor 1 is defective.
Since APP sensor 1 is part of the accelerator pedal assembly, you'll need to replace the accelerator pedal.
CASE 3: The resistance decreased/increased BUT there were gaps in the reading as you depressed/released the accelerator pedal. This test result lets you know that APP sensor 1 is defective.
Since APP sensor 1 is part of the accelerator pedal assembly, you'll need to replace the accelerator pedal.
TEST 3: APP Sensor 2 Resistance Tests (1 Of 2)
OK if you've reached this point you've tested APP sensor 1 and it has passed all of its tests.
Now we're going to start the first of two APP sensor 2 tests (which are very similar to the APP sensor 1 tests you just finished).
We'll start off our APP Sensor 2 diagnostic by testing the resistance between terminal G and terminal J.
The correct test result is for continuity to exist between these two APP sensor 2 terminals.
If continuity does not exist or the circuit has a short-circuit problem, then you can conclude that APP sensor 2 is defective.
OK, let's get started:
- 1
Disconnect the APP sensor assembly from its electrical connector.
- 2
Place your multimeter in Ohms mode.
- 3
Connect one multimeter test lead to terminal G.
- 4
Connect the other test lead to terminal J.
- 5
Your multimeter should read continuity.
I have usually gotten an Ohms reading of about 3.4 K Ohms at this point when testing a good APP sensor 2.
Let's examine your test results:
CASE 1: The multimeter registered continuity between terminals G and J. This is the correct test result.
The next test is to test the resistance of APP sensor 2 while depressing/releasing the accelerator pedal. For this test go to: TEST 4: APP Sensor 2 Resistance Tests (2 Of 2).
CASE 2: The multimeter DID NOT register continuity between terminals G and J. This test result tells you that APP sensor 2 is defective. Replace the accelerator pedal.
