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. This is a type D DTC.
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 input from APP 1 sensor is ignored. |
| • | This DTC will not turn on the Service Throttle Soon lamp by itself. |
| • | The throttle will operate normally as long as there is only one malfunction present. If there are two APP malfunctions present, the PCM will turn ON the Service Throttle Soon lamp and limit power. If a third APP malfunction is present, the Service Throttle Soon lamp will be ON and only allow the engine to operate at idle. |
Conditions for Clearing the MIL/DTC
| • | A History DTC will clear after forty consecutive warm-up cycles during which the diagnostic does not fail (the coolant temperature has risen 5°C (40°F) from start up coolant temperature and engine coolant temperature exceeds 71°C (160°F) that same ignition cycle). |
| • | Use of a Scan tool will clear the DTC codes. |
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 poor connections or the sensor itself. The least likely is a PCM problem.
A scan tool reads APP 1 position in volts. Should read about 0.45 to 0.95 volt with throttle closed and ignition ON or at idle. Voltage should increase at a steady rate as throttle is moved toward Wide Open Throttle (WOT). Also, 90% pedal travel is acceptable for correct APP operation. Scan APP sensor while depressing accelerator pedal with engine stopped and ignition ON. Display should vary from about 0.74 volt when throttle is closed to about 3.7 volts when throttle is held at Wide Open Throttle (WOT) position. A DTC P0122 will result if the signal or reference circuit are open.
Test Description
The number(s) below refer to the step number(s) 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 the DTC(s), use the Scan Tool Capture Info in order to record the Freeze Frame and the failure records for reference, as the data will be lost 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 table(s) first. Are there any additional DTCs stored? | -- | Go to the Applicable DTC Table | Go to Diagnostic Aids |
Is the APP 1 voltage greater than the specified value? | 4.75V | |||
5 |
Is the APP 1 voltage greater 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 poor 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 poor connection at the PCM and replace the terminal if necessary. Did the terminal require a replacement? | -- | ||
10 | Check for a poor electrical connection at the APP module and repair if necessary. Was a problem found? | -- | ||
11 | Replace the APP module. Refer to APP 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 that this diagnostic Passed? | -- | ||
14 | Use the Scan Tool in order to select Capture Info, Review Info. Are there any DTCs displayed that have not been diagnosed? | -- | Go to the Applicable DTC Table | System OK |
