Circuit Description
The accelerator pedal position (APP) module provides a voltage signal that changes relative to accelerator pedal position. There are three sensors located within the APP module that are scaled differently.
Conditions for Running the DTC
| • | The powertrain control module (PCM) performs this diagnostic trouble code (DTC) diagnostic continuously. |
| • | The ignition is in the ON position. |
Conditions for Setting the DTC
| • | The signal voltage on the APP 3 sensor is less than 0.25 volt. |
| • | All diagnostic conditions are met for 2 seconds. |
Action Taken When the DTC Sets
| • | The control module stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records. |
| • | The driver information center, if equipped, may display a message. |
Conditions for Clearing the DTC
| • | A current DTC Last Test Failed clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. |
| • | Clear the DTC with a scan tool. |
Diagnostic Aids
There are no driveability issues associated with the APP module unless a DTC is present. The most likely causes of this DTC are poor connections or the sensor. The least likely is a PCM problem.
A scan tool reads APP 3 position in volts. It should read about 4 volts with the throttle closed and the ignition ON or at idle. The voltage should decrease at a steady rate as the throttle is moved toward wide open throttle (WOT). Also, 90 percent pedal travel is acceptable for correct APP operation. Scan the APP 3 sensor while depressing the accelerator pedal with the engine OFF and the ignition ON. The display should vary from about 4 volts when the throttle is closed to about 2 volts when the throttle is held at wide open throttle (WOT).
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
Does the APP 3 voltage measure less than or equal to the specified value? | 0.25 V | Go to Step 4 | Go to Step 3 | |
3 | The DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids. If additional DTCs were stored, refer to those tables first. Are any additional DTCs stored? | -- | Go to Diagnostic Aids | |
4 |
Does the voltage measure at the specified value? | 5 V | Go to Step 5 | Go to Step 6 |
5 | Use DMM in order to probe the APP 3 signal circuit at the APP harness. Does the voltage measure at the specified value? | 4.8 V | Go to Step 10 | Go to Step 8 |
6 |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 7 |
7 | Check the 5-volt reference circuit for a proper connection at the PCM and replace terminal if necessary. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 |
8 |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9 |
9 | Check the APP 3 sensor signal circuit for a proper connection at the PCM and replace terminal if necessary. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 |
10 | Check for a proper electrical connection at the APP sensor. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11 |
11 | Replace the APP module. Refer to Accelerator Pedal Position Sensor Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- |
12 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- |
13 |
Does the DTC run and pass? | -- | Go to Step 14 | Go to Step 2 |
14 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
