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 ignition switch in the on position.
Conditions for Setting the DTC
| • | The voltage is less than 0.25 volts on APP 1. |
| • | All disgnostic set 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. The information is stored in the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | A History DTC will clear after forty consecutive warm-up cycles, if this or any other emmision related diagnostic does not report any failures. |
| • | 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. It should read about 0.45 to 0.95 volt with the throttle closed and ignition ON or at idle. 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. Display should vary from about 0.74 volt when the throttle is closed to about 3.7 volts when the throttle is held at the wide open throttle (WOT) position. A DTC P0122 will result if the signal or reference circuit are open.
Test Description
Number(s) below refer to the step number(s) 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 | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
Is the APP 1 voltage less than or equal to the specified value? | 0.25 V | |||
3 | The DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids. If additional DTCs were stored, refer to those table(s) first. Are any additional DTCs stored? | -- | Go to the applicable DTC table | Go to Diagnostic Aids |
Is the APP 1 voltage greater than the specified value? | 4.75 V | |||
5 |
Is the APP 1 voltage greater than the specified value? | 4.75 V | ||
6 |
Was the 5 volt reference circuit open or shorted to ground? | -- | ||
7 | Check the 5 volt reference circuit for a proper connection at the PCM and replace the terminal if necessary. Refer to Wiring Repairs in Wiring Systems. 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 proper connection at the PCM and replace terminal if necessary. Refer to Wiring Repairs in Wiring Systems. Did the terminal require replacement? | -- | ||
10 | Check for a proper electrical connection at the APP module and repair if necessary. Refer to Wiring Repairs . Did you perform a repair? | -- | ||
11 | Replace the APP module. Refer to Accelerator Pedal Position Module Replacement . Is the action complete? | -- | -- | |
12 |
Important: The new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. 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 |
