NOTE: If the ECM detects and stores a DTC, the ECM also stores the engine/vehicle operating conditions under which the DTC was set. Some of these conditions are displayed on the scan tool at the same time the DTC is displayed.

NOTE: Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for an active DTC.

NOTE: The APP Sensor is a device that contains 2 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.

NOTE: The APP Sensor 2 signal should always be approximately 1/2 the voltage of the APP Sensor 1 signal.

Inspect the APP Sensor for proper travel from the rest position to the fully depressed position.
Turn the ignition on.
Using a voltmeter, backprobe the APP Sensor 1 and APP Sensor 2 Signal circuits at the APP Sensor harness connector with the accelerator pedal in the at rest position.

Is the voltage between 0.42 and 0.51 volt for sensor 1 and 0.19 and 0.28 volt for sensor 2?

Yes

Go To 2

Go To4

2. APP SENSOR WIDE OPEN THROTTLE VOLTAGE

Fully depress the accelerator pedal.
Using a voltmeter backprobe the APP Sensor harness connector and read the voltage for APP Sensor 1 and APP Sensor 2 Signal circuits.

Is the voltage between 4.45 and 4.75 volts for #1 and 2.15 and 2.45 volts for #2?

Yes

Go To 3

Go To4

3. VERIFY APP SENSOR OPERATION

With the scan tool, read the APP Sensor 1 and APP Sensor 2 percentages (%).
With the accelerator pedal in the idle position, slowly depress the accelerator pedal until the pedal is fully depressed.

NOTE: The percentage readings for APP Sensors 1 and 2 should increase smoothly as the pedal is depressed.

NOTE: This test can also performed using a voltmeter by back probing each APP Sensor Signal circuit at the APP Sensor harness connector and observing the voltmeter for a smooth voltage change through the entire pedal travel.

Does the percentage (voltage) increase smoothly for both readings with the accelerator pedal travel?

Yes

Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

Replace the Accelerator Pedal Position Sensor in accordance with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.

4. VERIFY 5-VOLT SUPPLY AND SENSOR REFERENCE VOLTAGE A CIRCUITS

NOTE: Perform the rest of this diagnostic procedure on the individual APP Sensor Potentiometer (1 or 2) that did not display the correct voltages in the previous test.

Turn the ignition off.
Disconnect the APP Sensor harness connector.
Turn the ignition on.
Measure the voltage of the 5-Volt Supply circuit in the APP Sensor harness connector.

Is the voltage between 4.7 and 5.3 volts?

Yes

Go To 5

Go To13

5. VERIFY APP SIGNAL CIRCUIT

Turn the ignition off.
Connect a jumper wire between APP Sensor Signal circuit and the 5-volt supply circuit at the APP Sensor harness connector .
With the scan tool, read the PEDAL OUTPUT VOLTS.

Does the scan tool display between 4.0 and 5.5 volts?

Yes

Go To 6

Go To9

6. APP SENSOR GROUND CIRCUIT SHORTED TO VOLTAGE

Turn the ignition off.
Remove the jumper wire on the APP Sensor.
Disconnect the ECM harness connectors.
Remove the ASD Relay.
Connect a jumper wire between cavity 30 and cavity 87 of the ASD Relay connector.
Turn the ignition on.
Measure the voltage of the APP Sensor Ground circuit.

Is the voltage above 1.0 volt?

Yes

Repair the App Sensor Ground circuit for a short to voltage.
Perform ROAD TEST VERIFICATION - VER-2.

Go To 7

7. SENSOR GROUND OPEN

Turn the ignition off.
Remove the jumper wire and install the ASD relay.
Measure the resistance of the Sensor Ground circuit between the APP Sensor and the ECM.

Is the resistance below 10.0 ohms?

Yes

Go To 8

Repair the APP Sensor Ground circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.

8. ECM - SENSOR GROUND OPEN

Using a 12-volt test light connected to 12-volts, check the Sensor Ground circuit of the appropriate potentiometer.

Does the test light illuminate brightly?

Yes

Replace the Accelerator Pedal Position Sensor.
Perform ROAD TEST VERIFICATION - VER-2.

Replace and program the Engine Control Module in accordance with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.

9. APP SENSOR SIGNAL CIRCUIT OPEN

Turn the ignition off.
Remove the jumper wire on the APP Sensor.
Disconnect the ECM harness connectors.
Measure the resistance of the APP Sensor Signal circuit between the APP Sensor harness connector and the ECM harness connector.

Is the resistance below 10.0 ohms?

Yes

Go To 10

Repair the APP Sensor Signal circuit for an open
Perform ROAD TEST VERIFICATION - VER-2.

10. APP SENSOR SIGNAL CIRCUIT SHORTED TO GROUND

Disconnect the ECM harness connectors. Measure the resistance between ground and the APP Sensor Signal circuit.

Is the resistance below 1000 ohms?

Yes

Repair the APP Sensor Signal circuit for a short to ground.
Perform ROAD TEST VERIFICATION - VER-2.

Go To 11

11. APP SENSOR SIGNAL CIRCUIT SHORTED TO THE SENSOR GROUND CIRCUIT

Measure the resistance between the APP Sensor Signal circuit and the Sensor Ground circuit at the APP Sensor harness connector.

Is the resistance below 1000 ohms?

Yes

Repair the APP Sensor Signal and Sensor Ground circuits for a short together.
Perform ROAD TEST VERIFICATION - VER-2.

Go To 12

12. APP SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE

Remove the ASD Relay.
Connect a jumper wire between cavity 30 and cavity 87 of the ASD Relay connector.
Turn the ignition on.
Measure the voltage of the APP Sensor Signal circuit.

Is the voltage above 1.0 volt?

Yes

Repair the APP Sensor Signal circuit for a short to voltage.
Perform ROAD TEST VERIFICATION - VER-2.

Replace and program the Engine Control Module in accordance with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.

13. APP SENSOR 5-VOLT SUPPLY CIRCUITS OPEN

Turn the ignition off.
Disconnect the ECM harness connectors.
Measure the resistance of the Accelerator Pedal Position Sensor 5-volt Supply circuit between the APP Sensor harness connector and the ECM harness connector.

Is the resistance below 10.0 ohms?

Yes

Go To 14

Repair the Accelerator Pedal Position Sensor 5-Volt Supply circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.

14. APP SENSOR 5-VOLT SUPPLY CIRCUIT SHORTED TO SENSOR GROUND

Measure the resistance between the Accelerator Pedal Position Sensor 5-Volt Supply circuit and both Sensor Ground circuits in the APP Sensor harness connector.

Is the resistance above 1000 ohms?

Yes

Go To 15

Repair the 5-Volt Supply circuit for a short to the Sensor Ground circuit.
Perform ROAD TEST VERIFICATION - VER-2.

15. APP SENSOR 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND

Disconnect the ECM harness connectors. Measure the resistance between ground and the Accelerator Pedal Position Sensor 5-volt Supply circuit.

Is the resistance below 1000 ohms?

Yes

Repair the Accelerator Pedal Position Sensor 5-Volt Supply circuit for a short to ground.
Perform ROAD TEST VERIFICATION - VER-2.

Go To 16

16. APP SENSOR 5-VOLT SUPPLY SHORTED TO VOLTAGE

Remove the ASD Relay.
Connect a jumper wire between cavity 30 and cavity 87 of the ASD Relay connector.
Turn the ignition on.
Measure the voltage of the Accelerator Pedal Position Sensor 5-Volt Supply circuit in the ECM harness connector.

Is the voltage above 1.0 volt?

Yes

Repair the Accelerator Pedal Position Sensor 5-Volt Supply circuit for a short to voltage.

Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

Replace and program the Engine Control Module in accordance with the Service Information.
Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).