Circuit Description
The accelerator pedal position (APP) module provides a voltage signal that changes relative to the accelerator pedal position. There are 3 sensors located within the APP module that are scaled differently.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
| • | The voltage is less than 0.25 volts on APP 1. |
| • | The conditions 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 cause of this DTC are faulty connections or the sensor itself. The least likely cause of this DTC is a powertrain control module (PCM) condition.
A scan tool reads APP 1 position in volts. The APP 1 position should read approximately 0.45-0.95 volt with the throttle closed and the ignition ON or at idle. The voltage should increase 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 sensor while depressing the accelerator pedal with the engine stopped and the ignition ON. The display should vary from approximately 0.74 volt when the throttle is closed to approximately 3.7 volts when throttle is held at the WOT position. A DTC P0122 will result if the signal or the reference circuits are open.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step determines if DTC P0122 is the result of a hard failure or an intermittent condition.
-
This step checks the PCM and wiring.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
Is the APP 1 voltage 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 any additional DTCs were stored, refer to those tables first. Are there any additional DTCs stored? | -- | Go to Diagnostic Aids | |
Is the APP 1 voltage more than the specified value? | 4.75 V | Go to Step 10 | Go to Step 5 | |
5 |
Is the APP 1 voltage more than the specified value? | 4.75 V | Go to Step 6 | Go to Step 8 |
6 |
Was the 5-volt reference circuit open or shorted to ground? | -- | Go to Step 13 | Go to Step 7 |
7 | Check the 5-volt reference circuit for a faulty connection at the PCM and replace the terminal if necessary. Did the terminal require replacement? | -- | Go to Step 13 | Go to Step 12 |
8 |
Was the APP 1 signal circuit open or shorted to ground? | -- | Go to Step 13 | Go to Step 9 |
9 | Check the APP 1 sensor signal circuit for a faulty connection at the PCM and replace the terminal if necessary. Did the terminal require a replacement? | -- | Go to Step 13 | Go to Step 12 |
10 | Check for a faulty electrical connection at the APP module and repair the connection if necessary. Was a condition found? | -- | 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 scan tool indicate the diagnostic passed? | -- | Go to Step 14 | Go to Step 2 |
14 | Does the scan tool display any additional undiagnosed DTCs? | -- | System OK | |
