Data Display
The scan tool displays the module data. This information assists in
determining whether the following conditions exist:
| • | The module is operating properly. |
| • | The module is sending or receiving the proper data to and from
a particular system. |
The module uses data received from other systems in order to carry out
some functions. If the module receives the incorrect data from another system,
the module may function improperly. Use the scan tool in order to review
the data from the systems that interact with the module.
Displayed Input/Output Status
The scan tool also displays the module input/output status. Select the
module input/output status display in order to complete the following actions:
| • | Determine if the switched inputs/outputs can be properly interpreted. |
The display also indicates if the input/output has changed states. For
example, when you close a door, the scan tool displays the input status of
the door ajar switch as INACTIVE. When you open a door, the scan tool reads
ACTIVE. Use this kind of information when you diagnose one of the following
conditions:
| • | A malfunction associated with a particular module input |
| • | An input that is shared with another system |
Control Outputs
Use a scan tool in order to control the module output functions. When
you select the module output control, the scan tool can command the module
to turn an output on or off. This feature can be used to determine if the
module is able to control an output regardless of the inputs or any specific
program instructions. Once you select a test, the scan tool commands the
module to energize the selected output. The scan tool then displays the status
of the selected output. The displayed information represents only what was
commanded, not what action was actually taken. Verify that the module is
actually performing each of the selected output functions. You may need
to have the ignition in the RUN position in order to control the outputs.
