For a complete wiring diagram Refer to Section 8WPossible CausesAPP SENSOR 1APP SENSOR 21. APP SENSOR IDLE VOLTAGEIf there are any Accelerator Pedal Position Sensor DTC's active in the ECM, diagnose DTC's before continuing this test.The APP Sensor is a device that contains two separate potentiometer type sensors. Each sensor has its own 5-volt supply circuit, sensor ground circuit and signal circuit. The APP Sensor no longer incorporates a low-idle switch.The APP Sensor 1 signal should always be double the voltage of the APP Sensor 2 signal.Ensure the accelerator pedal is free from any restriction or binding before continuing.Turn the ignition on.With the scan tool, read the APP Sensor 1 and APP Sensor 2 Volts with the accelerator pedal in the at rest position.Does the scan tool display between 0.38 and 0.53 volt for sensor 1 and 0.19 and 0.27 volt for sensor 2?YesGo To 2NoCheck the APP Sensor circuits for proper resistance. If no problems are found, replace the APP Sensor in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)2. APP SENSOR 1While back probing, measure the voltage of the APP Sensor 1 Signal circuit at the ECM.Monitor the voltmeter while slowly pressing the accelerator pedal completely down.APP signals are displayed in voltage and percentage on the scan tool. Although APP 1 voltage is double APP 2 voltage, the percentage display of APP 1 and APP 2 should be within 2.5% of each other during all phases of accelerator pedal travel.Did the voltage increase smoothly with pedal travel?YesGo To 3NoReplace the Accelerator Pedal Position Sensor in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)3. APP SENSOR 2While back probing, measure the voltage of the APP Sensor 2 Signal circuit at the ECM.Monitor the voltmeter while slowly pressing the accelerator pedal completely down.APP signals are displayed in voltage and percentage on the scan tool. Although APP 1 voltage is double APP 2 voltage, the percentage display of APP 1 and APP 2 should be equal during all phases of accelerator pedal travel.Did the voltage increase smoothly with pedal travel?YesGo To 4NoReplace the Accelerator Pedal Position Sensor in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)4. APP SENSOR WIDE OPEN THROTTLE VOLTAGEFully depress the accelerator pedal.With the scan tool, read the voltage for APP Sensor 1 and APP Sensor 2.Does the scan tool display between 4.40 and 4.70 volts for sensor 1 and 2.20 and 2.35 volts for sensor 2?YesTest Complete.NoCheck the APP Sensor circuits for proper resistance. If o.k., replace the APP Sensor in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)