Powertrain Controls - ECM/PCM

DTC 25 Accelerator Pedal Position (APP) 2 Circuit High:

Accelerator Pedal Position (APP):

CIRCUIT DESCRIPTION
The Accelerator Pedal Position (APP) module provides a voltage signal that changes relative to accelerator position. There are three sensors located within the APP module that are scaled differently.

DIAGNOSTIC TROUBLE CODE (DTC) 25 WILL SET WHEN
Voltage is greater than 4.75 volts for 2 seconds on APP 2 sensor.

ACTION TAKEN (PCM will default to)
The input from APP 2 sensor is ignored. A current and history DTC will set but it will not turn "ON" the "Service Throttle Soon" lamp. The throttle will operate normally as long as there is only one malfunction present. If two different APP sensors have a malfunction, the "Service Throttle Soon" lamp will light and the Powertrain Control Module (PCM) will limit power. If three APP sensors have a malfunction present, the "Service Throttle Soon" lamp will light and the PCM will only allow the engine to operate at idle.

DTC 25 WILL CLEAR WHEN
The fault condition(s) no longer exist, and the ignition switch is cycled "OFF" then "ON."

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This step determines if DTC 25 is a hard failure or an intermittent condition.
2. This will check for an open in ground CKT 999.
3. This step checks the PCM and wiring.

DIAGNOSTIC AIDS
A Tech 1 scan tool reads APP 2 position in volts and should read about 4.5 volts with throttle closed and ignition "ON" or at idle. Voltage should decrease at a steady rate as throttle is moved toward WOT. Also, 90% pedal travel is acceptable for correct APP operation.
Refer to Intermittents. - Intermittent Malfunctions
Scan APP 2 signal while depressing accelerator pedal with engine stopped and ignition "ON." Display should vary from about 4.5 volts when throttle was closed to about 1.5 volts when throttle is held at Wide Open Throttle (WOT) position.