GM Service Manual Online
For 1990-2009 cars only

Object Number: 185076  Size: LF
Engine Controls Components
EGR, MAF and Accelerator Pedal Controls
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

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 PCM performs this DTC diagnostic continuously.
    • The ignition switch in the ON position.

Conditions for Setting the DTC

    • The 5 reference voltage on the APP 2 sensor is less than 4.8 volts.
    • All of the diagnostic set conditions met for 2 seconds.

Action Taken When the DTC Sets

    • The PCM will turn ON the Service Throttle Soon lamp and limit power.
    • The PCM records the operating conditions at the time the diagnostic fails. This information will store in the Failure Records.

Conditions for Clearing the MIL/DTC

    • A History DTC clears after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures
    • The use of a scan tool.

Diagnostic Aids

The most likely cause of this DTC is loose connectors or terminals. All 5 volt reference circuits must be checked for proper reference voltage. Volt meter accuracy is important.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

  1. This step will determine if there is a good voltage reference.

Step

Action

Value(s)

Yes

No

1

Important: Before clearing the DTCs, use the scan tool Capture Info to save the Freeze Frame and failure records for reference. The control module's data is deleted once the Clear Info function is used.

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

  1. Disconnect the APP sensor electrical connector.
  2. Turn the ignition ON leaving the engine OFF.
  3. With J 39200 connected to ground, check all the APP 5 volt reference circuits at the APP harness connector.

Is the voltage 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 additional DTCs were stored, refer to those table(s) first.

Are additional DTC(s) stored?

--

Go to the Applicable DTC Table

Go to Diagnostic Aids

4

  1. Turn the ignition OFF.
  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 it as necessary.

Was the 5 volt reference circuit shorted to ground?

--

Go to Step 6

Go to Step 5

5

Replace the PCM.

Important: The new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming

Is the action complete?

--

Go to Step 6

--

6

  1. Using the scan tool, clear the DTCs.
  2. Start the engine.
  3. Allow the engine to idle at normal operating temperature.
  4. Select DTC and the Specific DTC function.
  5. Enter the DTC number which was set.
  6. Operate the vehicle, with the Condition 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 the Applicable DTC Table

System OK