GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The accelerator pedal position (APP) module provides a voltage signal that changes relative to the accelerator pedal position. There are 3 sensors which are located within the APP module that are scaled differently.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

    • The reference voltage on the APP 3 is less than 4.8 volts.
    • The condition was met for 2 seconds.

Action Taken When the DTC Sets

    • The control module stores the DTC information into memory when the diagnostic runs and fails.
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
    • The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC

    • A current DTC Last Test Failed clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
    • Clear the DTC with a scan tool.

Diagnostic Aids

An intermittent may be caused by the following conditions:

    • Faulty connections
    • Rubbed-through wire insulation
    • A broken wire inside the insulation

All of the 5-volt reference circuits must be checked for proper reference voltage. Voltmeter accuracy is important.

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step will check all 5-volt reference circuits.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Disconnect the APP sensor electrical connector.
  2. Turn ON the ignition, with the engine OFF.
  3. With a DMM connected to ground, check all of the APP 5-volt reference circuits at the APP harness.

Does the voltage measure less than the specified value?

4.8 V

Go to Step 5

Go to Step 3

3

Are any other APP DTCs set?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 4

4

The DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids. If any additional DTCs were stored, refer to the applicable DTC tables first.

Are any additional DTCs stored?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Diagnostic Aids

5

  1. Turn OFF the ignition.
  2. Disconnect the PCM.
  3. Check the 5-volt reference circuit for a short to ground.
  4. If the 5-volt reference circuit is shorted to ground, repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you perform a repair?

--

Go to Step 7

Go to Step 6

6

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 7

--

7

  1. Use a scan tool in order to clear the DTCs.
  2. Start the engine.
  3. Allow the engine to idle until the normal operating temperature is reached.
  4. Select DTC and the Specific DTC function.
  5. Enter the DTC number that was set.
  6. Operate the vehicle within the Conditions for Setting this DTC until the scan tool indicates the diagnostic ran.

Does the scan tool indicate the diagnostic passed?

--

Go to Step 8

Go to Step 2

8

Does the scan tool display any additional undiagnosed DTCs?

--

Go to Diagnostic Trouble Code (DTC) List

System OK