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 Service Throttle Soon lamp will not illuminate when one APP DTC sets. The PCM will only illuminate the Service Throttle Soon lamp when multiple APP DTCs set. |
| • | The PCM records the operating conditions at the time the diagnostic fails. This information stores in the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | A History DTC will clear after 40 consecutive warm-up cycles if no failures are reported by this or any other emissions-related diagnostic. |
| • | Use a scan tool in order to clear the DTCs. |
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 PCM problem.
A scan tool reads APP 1 position in volts. It 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% 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 Wide Open Throttle (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 P0122 is the result of a hard failure or an intermittent condition.
-
This step checks the PCM and wiring.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Important: Before clearing any DTCs, use the Scan Tool Capture Info in order to save the Freeze Frame and Failure Records for reference. The Scan Tool loses data when the Clear Info function is used. Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||
Is the APP 1 voltage less than or equal to the specified value? | 0.25V | |||
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 the applicable DTC table | Go to Diagnostic Aids |
Is the APP 1 voltage more than the specified value? | 4.75V | |||
5 |
Is the APP 1 voltage more than the specified value? | 4.75V | ||
6 |
Was the 5-volt reference circuit open or shorted to ground? | -- | ||
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? | -- | ||
8 |
Was the APP 1 signal circuit open or shorted to ground? | -- | ||
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? | -- | ||
10 | Check for a faulty electrical connection at the APP module and repair the connection if necessary. Was a problem found? | -- | ||
11 | Replace the APP module. Refer to Accelerator Pedal Position Module Replacement . Is the action complete? | -- | -- | |
12 | Replace the PCM. Important: The new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | |
13 |
Does the Scan Tool indicate the diagnostic Passed? | -- | ||
14 | Does the Scan Tool display any additional undiagnosed DTCs? | -- | Go to the applicable DTC table | System OK |
