Description of On-Board Diagnostics

The IPC detects various malfunctions in the following components:
^ The sensors
^ The input switches
^ The components and systems the IPC controls
^ The components and systems with which the IPC communicates

When the IPC (or another microprocessor-controlled module) detects a malfunction, the following actions may occur:
^ An IPC indicator is activated.
^ A message is displayed on the driver message center.
^ A DTC is set in the IPC's (or another module's) memory.

Some DTCs may not cause an IPC message to be displayed. Some DTCs may not activate an IPC indicator lamp.

In order to display various IPC input and output parameters, any set DTC, and change the various IPC override options, use one of the following methods:
1. Enter the Vehicle Diagnostic System. Display the information on the IPC driver message center.
2. Connect a scan tool to the DLC.