APP Sensor Tests (2002-2003 4.2L Oldsmobile Bravada)

You can easily and accurately test the accelerator pedal position (APP) sensors on the 2002-2003 4.2L Oldsmobile Bravada with a multimeter resistance test.

In this tutorial, I'll explain the four multimeter resistance tests you need to perform step by step.

APPLIES TO: This tutorial applies to the following vehicles:

• 4.2L Oldsmobile Bravada: 2002, 2003.

WIRING DIAGRAM: The following TAC system wiring diagram may come in handy: TAC System Wiring Diagram (2002-2004 4.2L Oldsmobile Bravada, 2004-2005 4.2L Buick Rainier).

Symptoms Of A Bad APP Sensor

The PCM is in constant communication with APP sensor 1 and APP sensor 2 when the key is in the ON position or the engine is running.

This communication allows the PCM to set an APP sensor diagnostic trouble code when one of them fails.

You'll see one or more of the following diagnostic trouble codes when one of the APP sensor fails:

• P2120: Accelerator Pedal Position (APP) Sensor 1 Circuit.
• P2122: Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage.
• P2123: Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage.
• P2125: Accelerator Pedal Position (APP) Sensor 2 Circuit.
• P2127: Accelerator Pedal Position (APP) Sensor 2 Circuit Low Voltage.
• P2128: Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage.
• P2138: Accelerator Pedal Position (APP) Sensor 1 - 2 Correlation.

You'll also see one or more of the following symptoms:

• Your Oldsmobile Bravada will run in Reduced Engine Power mode.
• The engine starts and runs but when you try to accelerate your Oldsmobile Bravada, 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.

APP Sensor Terminal Pin Out Chart

Pin	Wire Color	Description
E	Dark blue (DK BLU)	APP Sensor 1 Signal
D	White with black stripe (WHT/BLK)	5 Volts
G	Purple (PPL)	Sensor Ground
H	Light blue (LT BLU)	APP Sensor 2 Signal
J	Tan (TAN)	5 Volts
K	Brown (BRN)	Sensor Ground

For a more detailed look at the APP sensor 1 and APP sensor 2 circuits, check out the TAC system wiring diagram here: TAC System Wiring Diagram (2002-2004 4.2L Oldsmobile Bravada, 2004-2005 4.2L Buick Rainier).

Where To Buy The Accelerator Pedal Assembly And Save

If you need to replace the accelerator pedal assembly, the following links will help you comparison shop for it:

Not sure if the APP sensor assembly 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: APP Sensor 1 Resistance Tests (1 Of 2)

To get started with the APP sensor assembly diagnostic tests, you'll check for continuity between terminals D and K (of APP sensor 1).

In case you're wondering:

• Terminal D receives 5 Volts DC from the PCM.
• Terminal K receives Ground from the PCM.

Before moving on to TEST 2, you'll make sure the circuit between terminals D and K hasn't suffered an open-circuit or a short-circuit problem.

NOTE: Connecting the multimeter to the indicated terminals can be challenging while the accelerator pedal assembly is bolted in place. I recommend removing the accelerator pedal assembly to quickly and easily connect your multimeter test leads to the indicated terminals.

These are the test steps:

1. 1

   Disconnect the APP sensor assembly from its electrical connector.

2. 2

   Place your multimeter in Ohms mode.

3. 3

   Connect one multimeter test lead to terminal D.

4. 4

   Connect the other multimeter test lead to terminal K.

5. 5

   Your multimeter should read continuity.
   
   You should see an Ohms value around 3K to 4K Ohms.

Let's examine your test results:

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

The next step is testing the resistance of APP sensor 1 as you depress/release the accelerator pedal. For this test go to: TEST 2: APP Sensor 1 Resistance Tests (2 Of 2).

CASE 2: The multimeter registered 0 Ohms (or a value very close to it) between terminals D and K. This test result confirms a short-circuit problem between terminals D and K.

With this test result, you can conclude the accelerator pedal assembly is defective and needs replacement.

CASE 3: The multimeter reports no continuity (the letters OL are displayed) between terminals D and K. This test result confirms an open-circuit problem between terminals D and K.

With this test result, you can conclude the accelerator pedal assembly is defective and needs replacement.