DTC P1125 Accelerator Pedal Position (APP) System. GMC Truck GMC P62 Commercial Chassis 1997

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 1997 🢒 GMC P62 Commercial Chassis 🢒 Engine 🢒 Engine Controls - 6.5L 🢒 DTC P1125 Accelerator Pedal Position (APP) System

Engine Controls Components
Engine Controls (Cell 22: Fuel Controls 5)
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 the accelerator pedal position. There are three sensors which are located within the APP module that are scaled differently.

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

•	The Service Throttle Soon lamp will not illuminate when one APP DTC sets. The PCM will only illuminate the Service Throttle Soon lamp when multiple APP DTCs set.

•	The PCM records the operating conditions at the time the diagnostic fails. This information stores in the Failure Records.

Conditions for Clearing the MIL/DTC

•	A History DTC will clear after forty consecutive warm-up cycles during which the diagnostic does not fail (the coolant temperature has risen 5°C (40°F) from the start up coolant temperature and the engine coolant temperature exceeds 71°C (160°F) during that same ignition cycle).

•	Use of a Scan tool will clear the DTC codes.

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 the sensor itself. 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 numbers below refer to the step numbers on the Diagnostic Table.

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 A Powertrain On Board Diagnostic (OBD) System Check
2	Disconnect the APP sensor electrical connector. Turn the ignition ON with the engine OFF. With J 39200 connected to ground, check all of the APP 5 volt reference circuits at the APP harness. Is the voltage less than the specified value?	4.8V	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 were stored, refer to the applicable DTC tables first. Are there any additional DTCs stored?	--	Go to the applicable DTC table	Go to Diagnostic Aids
4	Turn the ignition OFF. Disconnect the PCM and check the 5 volt reference circuit for a short to ground. If the 5 volt reference circuit is shorted to ground, repair as necessary. Was the 5 volt reference circuit shorted to ground?	--	Go to Step 6	Go to Step 5
5	Important: The new PCM must be programmed. Replace the PCM. Refer to PCM Replacement/Programming . Is the action complete?	--	Go to Step 6	--
6	Using the Scan Tool, clear the DTCs. Start engine and idle at normal operating temperature. Select DTC, Specific, then enter the DTC number which was set. 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 the applicable DTC table	System OK