GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2001 🢒 Chevy C Cab/Chassis HD (GMT 400) 🢒 Engine 🢒 Engine Controls - 6.5L (L65) 🢒 DTC P0228

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 signal voltage on the APP 3 sensor is more than 4.75 volts.
    • All diagnostic 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 APP 3 position in volts. It 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 correct APP operation. Scan the APP 3 sensor while depressing the accelerator pedal with the engine OFF 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 wide open throttle (WOT).

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 voltage measure at least 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 low reference circuit at the APP sensor harness connector with a unpowered test lamp connected to battery voltage.

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 low reference circuit at the APP harness connector.

Does the scan tool display the APP 3 voltage 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 as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 12

7
  1. Check for an open sensor low reference circuit.
  2. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

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 the low reference 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 repair?

--

Go to Step 14

--

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

Did you find and correct the condition?

--

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 poor electrical connection at the PCM sensor.
  2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 13

13

Replace the PCM. Refer to Powertrain Control Module Replacement Powertrain Control Module (PCM) Replacement.

Did you complete the replacement?

--

Go to Step 14

--

14
  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 15

Go to Step 2

15

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