DTC 63

DTC 63 Accelerator Pedal Position (APP) 3 Circuit High:

Accelerator Pedal Position (APP) 3 Circuit High:

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) 63 WILL SET WHEN
Voltage is greater than 4.75 volts for 2 seconds on APP 3 sensor.

ACTION TAKEN (Powertrain Control Module (PCM) will default to)
The input from APP 3 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 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 63 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 will determine if DTC 63 is the result of a hard failure or an intermittent condition.
2. This step checks the PCM and wiring.
3. This will check for an open in ground CKT 994 and PCM.

DIAGNOSTIC AIDS
A scan tool reads APP 3 position in volts. Should read about 4.0 volts with throttle closed and ignition "ON" or at idle. Voltage should decrease at a steady rate as throttle is moved toward Wide Open Throttle (WOT).
Also, 90% pedal travel is acceptable for correct APP operation.
Scan APP 3 sensor while depressing accelerator pedal with engine stopped and ignition "ON." Display should vary from about 4.0 volts when throttle was closed to about 2.0 volts when throttle is held at Wide Open Throttle (WOT) position.