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Theory of Operation The Accelerator Pedal Position Sensor (APP) is a device that contains 2 separate potentiometer type sensors. Each The APP Sensor 2 signal should always be approximately 1/2 the voltage of the APP Sensor 1 signal. Possible Causes APP SENSOR OPERATION APP SENSOR CIRCUIT 1 HIGH RESISTANCE APP SENSOR CIRCUIT 2 HIGH RESISTANCE Diagnostic Test 1. APP SENSOR IDLE VOLTAGE Inspect the Accelerator Pedal Position Sensor for proper travel from the Turn the ignition on. With the accelerator pedal in the rest position, use a voltmeter to back- Is the voltage between 0.42 and 0.51 volt for sensor 1 and 0.19 Yes >> Go To 2 No >> Check the wiring and connectors related to the Accelerator Pedal Position Sensor. If OK, replace the Accelerator Pedal Perform the ECM Verification Test Ver. 1 (Refer to 9 - 2. APP SENSOR While back probing, measure the voltage of the (K23) Accelerator Pedal Monitor the voltmeter while slowly pressing the accelerator pedal com- Did the voltage for both sensors increase smoothly with pedal Yes >> Go To 3 No >> Replace the Accelerator Pedal Position Sensor in accor- dance with the Service Information. Perform the ECM Verification Test Ver. 1 (Refer to 9 - 9 - 650 ENGINE DIESEL DIAG KJ |