P0123

Diagnostic Chart:

Wiring Diagram:

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
- Voltage is greater than 4.75 volts on APP 1 sensor.
- Condition met for 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The input from APP 1 sensor is ignored.
- A current and history DTC will set but it will not turn on the Service Throttle Soon lamp.
- Throttle will operate normally as long as there is only one malfunction present. If there are two APP malfunctions present, the Powertrain Control Module (PCM) will turn ON the Service Throttle Soon lamp and limit power. If a third APP malfunction is present, the Service Throttle Soon lamp will be ON and only allow the engine to operate at idle.

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.

DIAGNOSTIC AIDS
A scan tool reads APP 1 position in volts. Should read about 0.45 to 0.95 volt with throttle closed and ignition ON or at idle. Voltage should increase at a steady rate as throttle is moved toward Wide Open Throttle (WOT). Also, 90% pedal travel is acceptable for correct 0 APP operation. Scan APP 1 sensor while depressing accelerator pedal with engine stopped and ignition ON. Display should vary from about 0.74 volt when throttle was closed to about 3.7 volt when throttle is held at Wide Open Throttle (WOT) position. A P0123 will result if the ground circuit is open or the signal circuit is shorted to voltage. Refer to Intermittents Symptoms.

TEST DESCRIPTION
Number(s) below refer to the Step number(s) on the Diagnostic Table.

2. This Step determines if DTC P0123 is the result of a hard failure or an intermittent condition.
3. This Step checks the PCM and wiring.