Circuit Description
The accelerator pedal position (APP) sensors 1 and 2 are located within the accelerator pedal assembly. Each sensor has the following circuits:
| • | A 5-volt reference circuit |
| • | A low reference circuit |
| • | A signal circuit |
This provides the powertrain control module (PCM) with a signal voltage proportional to accelerator pedal movement. The APP sensor 1 signal voltage at rest position is near the low reference and increases as the pedal is actuated. The APP sensor 2 signal voltage at rest position is near the 5-volt reference and decreases as the pedal is actuated.
Conditions for Running the DTC
| • | The battery voltage is more than 5.23 volts. |
| • | DTCs P1275, P1280, P1635, or P1639 are not set. |
| • | The accelerator pedal is leaving the idle position. |
Conditions for Setting the DTC
The voltage difference between APP sensor 1 and APP sensor 2 exceeds a predetermined value.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records. |
| • | The control module commands the TAC system to operate in the Reduced Engine Power mode. |
| • | A message center or an indicator displays Reduced Engine Power. |
| • | Under certain conditions the control module commands the engine OFF. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL after 3 consecutive drive trips that the diagnostic runs and does not fail. |
| • | A History DTC clears after 40 consecutive warm up cycles in which no failures are reported by this diagnostic or any other emission related diagnostic. |
| • | The scan tool clears the MIL/DTC. |
Diagnostic Aids
The PCM compares the signal of each of the accelerator pedal position sensor to each other throughout the entire range of operation. Clear the DTCs and actuate the pedal through the entire range with the ignition ON and the engine OFF.
Use the J 35616 Connector Test Adapter Kit for any test that requires probing the PCM harness connector or a component harness connector. Using this kit will prevent damage to the harness connector terminals.
Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems for intermittent conditions.
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views | ||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||
Using a scan tool, observe the DTC information. Is DTC P1120, P1220, P1275, P1280, P1635, or P1639 also set? | -- | Go to Step 3 | ||||||||
3 |
Did any of the circuits measure more than the specified value? | 5 Ohms | Go to Step 5 | Go to Step 4 | ||||||
4 |
Did you find and correct the condition? | -- | Go to Step 7 | Go to Step 6 | ||||||
5 | Repair the high resistance in the circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 7 | -- | ||||||
6 | Replace the APP sensor. Refer to Accelerator Pedal Position Sensor Replacement . Did you complete the replacement? | -- | Go to Step 7 | -- | ||||||
7 |
Does the DTC run and pass? | -- | Go to Step 8 | Go to Step 2 | ||||||
8 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |||||||
