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 PCM performs this DTC diagnostic continuously. |
Conditions for Setting the DTC
• | The signal voltage on the APP 2 sensor is less than 0.25 volts. |
• | All of the diagnostic set conditions met for 2 seconds. |
Action Taken When the DTC Sets
• | The input from APP 2 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
sensor malfunction present. If two different APP sensors have a malfunction,
the service throttle soon lamp will light and the PCM will limit power.
If three APP sensors have a malfunction present, the service throttle
soon lamp will light and the PCM will only allow the engine to operate
at idle. |
Conditions for Clearing the MIL/DTC
• | A History DTC clears after forty consecutive warm-up cycles, if
this or any other emission related diagnostic does not report any failures. |
Diagnostic Aids
Important: Remove any debris from the PCM module connector surfaces before servicing
the PCM module. Inspect the PCM module connector gaskets when diagnosing/replacing
the module. Ensure that the gaskets are installed correctly. The gaskets
prevent contaminate intrusion into the PCM module.
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 itself. The least likely is a PCM problem.
A scan tool reads APP 2 position in volts and should read about
4.5 volts with throttle closed and ignition ON or at idle. Voltage
should decrease at a steady rate as throttle is moved toward WOT.
Also, 90 percent pedal travel is acceptable for correct APP
operation. Scan APP 2 sensor while depressing accelerator pedal
with engine stopped and ignition ON. Display should vary from about
4.5 volts when throttle was closed to about 1.5 volts
when throttle is held at wide open throttle (WOT) position.