GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1997 🢒 GMC K Pickup - 4WD 🢒 Engine 🢒 Engine Controls - 6.5L 🢒 DTC P1125 Accelerator Pedal Position (APP) System

Object Number: 56421 Size: LF
Engine Controls Components
DIESEL PCM, MAF, EGR, APP, WASTEGATE
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. This is a type D DTC.

Conditions for Setting the DTC

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.

Conditions for Clearing the MIL/DTC
    • A History DTC will clear when forty consecutive warm-up cycles that the diagnostic does not fail (coolant temperature has risen 5°C (40°F) from start up coolant temperature and engine coolant temperature exceeds 71°C (160°F) that same ignition cycle.
    • 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 DTCs use the scan tool Capture Info to record freeze frame and failure records for reference, as data will be lost when Clear Info function is used.

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, select DTC, Clear Info.
  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 until the Scan Tool indicates that the diagnostic Ran.

Does the Scan Tool indicate that the diagnostic Passed?

--

Go to Step 7

Go to Step 2

7

Using the Scan Tool, select Capture Info, Review Info.

Are any DTCs displayed that have not been diagnosed?

--

Go to the Applicable DTC Table

System OK