For a complete wiring diagram Refer to Section 8WThe Accelerator Pedal Position Sensor contains two independent three wire inductive sensors. Each sensor provides independent pedal position signals to the ECM. The raw voltage signal from APP 1 sensor is 2 times the raw voltage signal from APP 2. Although the raw voltage signals differ, the scan tool converts and displays these voltages as matching percentages of pedal travel.When Monitored:With the ignition on.Set Condition:The APP Sensor #2 signal circuit is above 2.5 volt for 0.3 second.Possible CausesINTERMITTENT DTC(F856) ACCELERATOR PEDAL POSITION SENSOR NO. 2 5 VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE(K29) ACCELERATOR PEDAL POSITION SENSOR NO. 2 SIGNAL CIRCUIT SHORTED TO VOLTAGE(K400) ACCELERATOR PEDAL POSITION SENSOR NO. 2 SENSOR GROUND CIRCUIT SHORTED TO VOLTAGE(K29) ACCELERATOR PEDAL POSITION SENSOR NO. 2 SIGNAL CIRCUIT SHORTED TO THE (F856) ACCELERATOR PEDAL POSITION SENSOR NO. 2 5 VOLT SUPPLY CIRCUIT OR (F855) ACCELERATOR PEDAL POSITION SENSOR NO. 1 5 VOLT SUPPLY CIRCUIT(F856) ACCELERATOR PEDAL POSITION SENSOR NO. 2 5 VOLT SUPPLY CIRCUIT OPEN OR HIGH RESISTANCE(K29) ACCELERATOR PEDAL POSITION SENSOR NO. 2 SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE(K400) ACCELERATOR PEDAL POSITION SENSOR NO. 2 SENSOR GROUND CIRCUIT OPEN OR HIGH RESISTANCEACCELERATOR PEDAL POSITION SENSORENGINE CONTROL MODULE (ECM)Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)1. DTC IS ACTIVEIf any Sensor Reference or Sensor Supply voltage DTCs are present, perform the applicable diagnostic procedure before continuing with this test.The APP Sensor 2 signal should always be approximately 1/2 the voltage of the APP Sensor 1 signal.Ignition on, engine not running.With the scan tool, Clear DTCs in the Engine Control Module (ECM).Fully depress and release the Accelerator Pedal several times.With the scan tool, select View DTCs.Is the status Active for this DTC?YesGo To 2 NoRefer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)2. ACCELERATOR PEDAL POSITION SENSOR CIRCUIT SHORTED TO VOLTAGE

Disconnect the Engine Control Module (ECM) harness connector.Remove the ASD Relay from the TIPM.Connect a jumper wire between cavity 30 and cavity 87 of the ASD Relay Connector.Turn the ignition on.Measure the voltage of the (F856) Accelerator Pedal Position Sensor No. 2 5 Volt Supply circuit in the Accelerator Pedal Position Sensor harness connector.Measure the voltage of the (K29) Accelerator Pedal Position Sensor No. 2 Signal circuit in the Accelerator Pedal Position Sensor harness connector.Measure the voltage of the (K400) Accelerator Pedal Position Sensor No. 2 Sensor Ground circuit in the Accelerator Pedal Position Sensor harness connector.Is there voltage present on any of the circuits?YesRepair the appropriate circuit that has voltage present for a short to voltage.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo to 33. (K29) ACCELERATOR PEDAL POSITION SENSOR NO. 2 SIGNAL CIRCUIT SHORTED TO THE 5 VOLT SUPPLY CIRCUIT

Turn the ignition off.Remove the jumper wire and install the ASD Relay.Measure the resistance between the (K29) Accelerator Pedal Position Sensor No. 2 Signal circuit and the (F856) Accelerator Pedal Position Sensor No. 2 5 Volt Supply circuit in the Accelerator Pedal Position Sensor harness connector.Measure the resistance between the (K29) Accelerator Pedal Position Sensor No. 2 Signal circuit and the (F855) Accelerator Pedal Position Sensor No. 1 5 Volt Supply circuit in the Accelerator Pedal Position Sensor harness connector.Is the resistance above 1000 ohms for both of the circuits?YesGo to 4NoRepair the shorted (K29) Accelerator Pedal Position Sensor No. 2 Signal circuit.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)4. ACCELERATOR PEDAL POSITION SENSOR CIRCUIT OPEN OR HIGH RESISTANCE

Measure the resistance of the (F856) Accelerator Pedal Position Sensor No. 2 5 Volt Supply circuit between the Accelerator Pedal Position Sensor harness connector and the Engine Control Module (ECM) harness connector.Measure the resistance of the (K29) Accelerator Pedal Position Sensor No. 2 Signal circuit between the Accelerator Pedal Position Sensor harness connector and the Engine Control Module (ECM) harness connector.Measure the resistance of the (K400) Accelerator Pedal Position Sensor No. 2 Sensor Ground circuit between the Accelerator Pedal Position Sensor harness connector and the Engine Control Module (ECM) harness connector.Is the resistance below 10.0 ohms for each of the circuits?YesGo to 5NoRepair the appropriate circuit for an open circuit or high resistance.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)5. ACCELERATOR PEDAL POSITION SENSOR

Connect the Engine Control Module (ECM) harness connector.Connect a jumper wire between the (K400) Accelerator Pedal Position Sensor No. 2 Sensor Ground circuit and the (K29) Accelerator Pedal Position Sensor No. 2 Signal circuit in the Accelerator Pedal Position Sensor harness connector.Turn the ignition on.With the scan tool, Clear DTCs.Fully depress and release the Accelerator Pedal several times.With the scan tool, select View DTCs.The scan tool should display an Accelerator Pedal Position Sensor No. 2 low voltage or short to ground DTC with the jumper wire in place.Does the scan tool display the DTC as described above?YesReplace the Accelerator Pedal Position Sensor in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo to 66. ENGINE CONTROL MODULE (ECM)Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Accelerator Pedal Position Sensor and the Engine Control Module (ECM).Look for any chafed, pierced, pinched, or partially broken wires.Look for broken, bent, pushed out or corroded terminals.Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.Look for the data to change or for the DTC to reset during the wiggle test.Refer to any Technical Service Bulletins that may apply.Were any problems found?YesRepair as necessary.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoReplace the Engine Control Module (ECM) in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)