GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2002 🢒 Express 🢒 Body and Accessories 🢒 Theft Deterrent 🢒 DTC P0228

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 switch is in the ON position.

Conditions for Setting the DTC
    • The voltage is more than 4.75 volts for 2 seconds on the APP 3 sensor.
    • The 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 cause of this DTC are poor connections or the sensor itself. The least likely is a powertrain control module (PCM) condition.

A scan tool reads the APP 3 position in volts. The scan tool should read about 4 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 wide open throttle (WOT). Also, 90 percent pedal travel is acceptable for a correct APP operation. Scan the APP 3 sensor while depressing the accelerator pedal with the engine stopped and the ignition ON. The display should vary from about 4 volts when the throttle is closed to about 2 volts when the throttle is held at the WOT position.

Test Description

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

  1. This step determines if DTC P0228 is a hard failure or an intermittent condition.

    2.

  2. This step checks for an open in the ground circuit.

    3.

  3. This step checks for a short to power or a bad APP module.

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 3 display on the scan tool.

Does APP 3 display measure more than or equal to the specified value?

4.75 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 are stored, refer to the applicable DTC tables first.

Are any additional DTCs stored?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Diagnostic Aids

4
  1. Disconnect the APP sensor harness connector.
  2. Probe the APP 3 sensor ground circuit at the APP sensor harness connector with an J 35616-200 Unpowered Test Lamp connected to B+.

Does the test lamp illuminate?

--

Go to Step 5

Go to Step 7

5

Use a fused jumper wire in order to jump the APP 3 signal circuit to the APP 3 ground circuit at the APP harness connector.

Does the scan tool display the APP 3 voltage as less than the specified value?

0.25 V

Go to Step 8

Go to Step 6

6
  1. Check for an open on the APP 3 sensor signal circuit.
  2. If the APP 3 sensor signal circuit is open, repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you perform a repair?

--

Go to Step 14

Go to Step 12

7
  1. Check for an open sensor ground circuit.
  2. If you find a condition, repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you perform a repair?

--

Go to Step 14

Go to Step 12

8

  1. Verify the ignition is ON, with the engine OFF.
  2. Verify the APP harness is still disconnected from the APP module.
  3. With a DMM set to the mA scale, measure the current between the APP 3 signal circuit and at the ground circuit at the harness connector.

Does the current measure more than the specified value?

30 mA

Go to Step 9

Go to Step 10

9

Repair the short to voltage on the APP 3 signal circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the replacement?

--

Go to Step 14

--

10
  1. Check for a faulty electrical connection at the APP sensor.
  2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you perform a repair?

--

Go to Step 14

Go to Step 11

11

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

Did you complete the replacement?

--

Go to Step 14

--

12
  1. Check for a faulty electrical connection at the PCM.
  2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you perform a repair?

--

Go to Step 14

Go to Step 13

13

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 14

--

14
  1. Use a scan tool in order to clear the DTCs.
  2. Start the engine.
  3. Allow the engine to idle until the engine reaches a normal operating temperature.
  4. Select the DTC and the Specific DTC functions.
  5. Enter the DTC number that was set.
  6. Operate the vehicle within the Conditions for Setting the DTC until the scan tool indicates the diagnostic ran.

Does the scan tool indicate the diagnostic passed?

--

Go to Step 15

Go to Step 2

15

Does the scan tool display any additional undiagnosed DTCs?

--

Go to Diagnostic Trouble Code (DTC) List

System OK