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 accelerator pedal position. There are three sensors located within the APP module that are scaled differently.

Conditions for Running the DTC

    • The powertrain control module (PCM) performs this diagnostic trouble code (DTC) diagnostic continuously.
    • The ignition is in the ON position.

Conditions for Setting the DTC

    • The reference voltage on the APP 2 sensor is less than 0.25 volts.
    • All of the diagnostic set conditions are 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

There are no driveability issues associated with the APP module unless a DTC is present. The most likely causes of this DTC are poor connections or the sensor. The least likely is a PCM problem.

A scan tool reads the APP 2 position in volts, and should read about 4.5 volts with the throttle closed and the ignition ON or at idle. The voltage should decrease at a steady rate as the throttle is moved toward WOT. Also, 90 percent pedal travel is acceptable for correct APP operation. Scan the APP 2 sensor while depressing the accelerator pedal with the engine OFF and ignition ON. The display should vary from about 4.5 volts when the throttle is closed to about 1.5 volts when the throttle is held at wide open throttle (WOT).

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step determines if DTC P0222 is the result of a hard failure or an intermittent condition.

  2. This step checks the PCM and wiring.

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. Turn ON the ignition, with the engine OFF.
  2. With the throttle closed, observe the APP 2 voltage on the scan tool.

Does the APP 2 voltage measure less than or equal to the specified value?

0.25 V

Go to Step 4

Go to Step 3

3

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

Are any additional DTCs stored?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Diagnostic Aids

4

  1. Disconnect the APP sensor electrical connector.
  2. Use the DMM in order to probe the APP 2, 5-volt reference circuit at APP harness.

Does the APP 2 voltage measure more than the specified value?

5 V

Go to Step 5

Go to Step 6

5

Use the DMM in order to probe APP 2 sensor signal circuit at the APP sensor harness.

Does the APP 2 voltage measure more than the specified value?

4.8 V

Go to Step 10

Go to Step 8

6

  1. Turn OFF the ignition.
  2. Disconnect the PCM and check the 5-volt reference circuit for an open or short to ground.
  3. If the 5-volt reference circuit is open or shorted to ground, repair the circuit as necessary.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 7

7

  1. Check the 5-volt reference circuit for a proper connection at the PCM .
  2. Replace the terminal if necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 12

8

  1. Turn OFF the ignition.
  2. Disconnect the PCM, and check the APP 2 signal circuit for an open, or a short to ground.
  3. If the APP 2 sensor signal circuit is open or shorted to ground, repair it as necessary.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 9

9

  1. Check the APP 2 sensor signal circuit for a proper connection at the PCM.
  2. Replace the terminal if necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 12

10

Check for a proper electrical connection at the APP sensor.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 11

11

Replace the APP module. Refer to Accelerator Pedal Position Sensor Replacement .

Did you complete the replacement?

--

Go to Step 13

--

12

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 13

--

13

  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

--

Go to Step 14

Go to Step 2

14

With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK