Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC P1125: Accelerator Pedal Position (APP) SystemDiagnostic Fault Information
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
APP 1 Sensor 5-Volt Reference | P0642 | P2122 | -- |
APP 1 Sensor Signal | P2122 | P2122 | P2123 |
APP 1 Sensor GND | -- | P2123 | -- |
APP 2 Sensor 5-Volt Reference | P0652 | P2127 | -- |
APP 2 Sensor Signal | P2127 | P2128 | P2128 |
APP 2 Sensor GND | -- | P2128 | -- |
APP 3 Sensor 5-Volt Reference | P0698 | P2132 | -- |
APP Sensor Signal | P2132 | P2133 | P2133 |
APP 3 Sensor GND | -- | P2133 | -- |
Typical Scan Tool Data
APP Sensor | Actual Pedal Position | (%) Depressed as Observed on a Scan Tool | Voltage as Observed on a Scan Tool |
|---|---|---|---|
Operating Conditions: Ignition ON Parameter Normal Range: 0-100 | |||
APP Sensor 1 | Pedal at reset | 0 | 0.52-0.80 |
APP Sensor 1 | Pedal at full travel | 100 | 2.12-2.78 |
APP Sensor 2 | Pedal at reset | 0 | 4.25-4.53 |
APP Sensor 2 | Pedal at full travel | 100 | 2.24-2.93 |
APP Sensor 3 | Pedal at reset | 0 | 3.95-4.13 |
APP Sensor 3 | Pedal at full travel | 100 | 2.69-3.16 |
Circuit/System Description
The accelerator pedal position (APP) sensor is mounted on the accelerator pedal control assembly. The sensor is made up of three individual sensors within one housing. The APP sensor 1, APP sensor 2, and APP sensor 3 are potentiometer type sensors. The engine control module (ECM) supplies 5 volts to the APP sensor on the 5-volt reference circuits. The ECM also provides a ground on the low reference circuits. The APP sensor provides a signal to the ECM on the APP sensor signal circuits, which is relative to the position changes of the accelerator pedal angle. The APP sensor 1 signal voltage is low at rest and increases as the pedal is depressed. The APP sensor 2 signal voltage is high at rest and decreases as the pedal is depressed. The APP sensor 3 signal is high at rest and decreases as the pedal is depressed.
Conditions for Running the DTC
DTCs P0642, P0643, P0652, P0653, P0698 and P0699 are not set.
Conditions for Setting the DTC
One or more of the APP sensor signals contain an open or short circuit.
Action Taken When the DTC Sets
DTC P1125 is a Type B DTC.
Conditions for Clearing the DTC
DTC P1125 is a Type B DTC.
Diagnostic Aids
Inspect for any recent engine mechanical repairs. An incorrectly installed APP sensor will cause this DTC to set.
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Important: If DTCs P0642, P0643, P0652, P0653, P0698 and P0699 are set, test and repair those DTCs first.
Verify the integrity of the accelerator pedal, accelerator pedal position (APP) sensor by inspecting for the following conditions:
| • | Damaged components |
| • | Loose or improper installation |
Circuit/System Testing
Important: You must perform Circuit/System Verification before proceeding with Circuit/System Testing.
- With the ignition ON, test for 4.8-5.2 volts between the applicable APP sensor 5-volt reference circuit and ground.
- Using a DMM, measure the voltage between the 5-volt reference circuit and a low reference circuit.
- Install a 3-amp fused jumper wire between the applicable signal circuit and the applicable 5-volt reference circuit for APP sensor 2 and 3. Verify that the scan tool accelerator position (APP) sensor parameter is greater than 5 volts.
- Install a 3-amp fused jumper wire between the applicable signal circuit and the applicable 5-volt reference circuit for APP sensor 1. Verify that the DMM volt meter scan tool accelerator position (APP) sensor parameter is greater than 5 volts.
| ⇒ | If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the control module. |
| ⇒ | If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the control module. |
| ⇒ | If less than 4.8 volts, test the low reference circuit for an open circuit. |
| ⇒ | If less than 4.8 volts, test the applicable signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the control module. |
| ⇒ | If more than 5.2 volts, replace the accelerator pedal assembly. |
| ⇒ | If less than 4.8 volts, test the applicable signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the control module. |
| ⇒ | If more than 5.2 volts, replace the accelerator pedal assembly. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for engine control module (ECM) replacement, setup, and programming |
