GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1998 🢒 GMC Suburban - 2WD 🢒 DTC 🢒 DTC P1125 Accelerator Pedal Position (APP) System

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 ignition switch in the ON position.

Conditions for Setting the DTC

The PCM has recognized an intermittent APP fault and there are no other current APP faults stored.

Action Taken When the DTC Sets
    • Vehicle will operate at limited power.
    • The PCM will not illuminate the malfunction indicator lamp (MIL).
    • The PCM records the operating conditions at the time the diagnostic fails. This information is stored 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

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

Test Description

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

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

Step

Action

Value(s)

Yes

No

1

Important: Before clearing any DTCs, use the scan tool Capture Info to save freeze frame and failure records for reference, as the Scan tool loses data when using the Clear Info function.

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

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

Is voltage less than specified value?

4.8 V

Go to Step 4

Go to Step 3

3

DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids. If additional DTCs were stored refer to the applicable DTC table(s) first.

Are any additional DTCs stored?

--

Go to the Applicable DTC Table

Go to Diagnostic Aids

4
  1. 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 engine and idle at normal operating temperature.
  3. Select DTC, Specific, then enter the DTC number which was set.
  4. Operate the vehicle, with 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 the Applicable DTC Table

System OK