P0122

DTC P0122 Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage






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. This is a type C DTC.

Conditions for Setting the DTC

^ Voltage is less than .25 volts on APP 1.
^ Conditions met for 2 seconds.

Action Taken When the DTC Sets

^ The input from APP sensor is ignored.
^ A current and history DTC will set but it will not turn on the "Check Throttle" lamp.
^ The throttle will operate normally as long as there is only one sensor malfunctioning. If two different APP sensors have a malfunction, the "Check Throttle" 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.

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).
^ Use of a Scan Tool

Diagnostic Aids

A scan tool reads APP position in volts. It should read about .45 to .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 APP operation. Scan APP sensor while depressing accelerator pedal with engine stopped and ignition "ON". Display should vary from about .74 volt when throttle is closed to about 3.7 volts when throttle is held at Wide Open Throttle (WOT) position. A DTC P0122 will result if the signal or reference circuit are open.

Test Description

Number(s) below refer to the number(s) on the diagnostic table.

2. This step determines if P0122 is the result of a hard failure or an intermittent condition.

4. This step checks the PCM and wiring.