GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2001 🢒 Express 🢒 Engine 🢒 Engine Controls - 6.5L (L65) 🢒 DTC P1125

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 in the ON position.

Conditions for Setting the DTC

The powertrain control module (PCM) has recognized an intermittent APP fault and there are no other current APP faults stored.

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 a malfunctioning sensor. The least likely is a PCM problem.

A DTC P1125 will set along with multiple APP DTCs. All other DTCs should be diagnosed first.

Test Description

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

  1. This step determines if DTC P1125 is a hard failure or an intermittent condition.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

1

Important: Before clearing the DTCs, use the scan tool Capture Info to save the Freeze Frame/Failure Records for reference. The data in the control module is deleted once the Clear Info function is used.

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 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 4

Go to Step 3

3

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

Are there any additional DTCs stored?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Diagnostic Aids

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

Was the 5-volt reference circuit shorted to ground?

--

Go to Step 6

Go to Step 5

5

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 6

--

6
  1. Use the scan tool in order to clear the DTCs.
  2. Start the engine.
  3. Allow the engine to idle until the engine reaches the normal operating temperature.
  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 7

Go to Step 2

7

Does the scan tool display any additional undiagnosed DTCs?

--

Go to Diagnostic Trouble Code (DTC) List

System OK