The scan tool has the capability of displaying various HVAC information. This information assists in determining whether or not the HVAC module is sending or receiving the proper data to various systems/components. The HVAC module uses data received from other systems in order to carry out some functions. Therefore, if the HVAC module receives the incorrect data from another system, the HVAC system may function improperly. Use the scan tool in order to review the data that interacts with the HVAC system.

The scan tool can also display the status of the various HVAC inputs. Select the HVAC input status display in order to read the data and determine if the inputs can be properly interpreted. The display also indicates if the input has changed states. For example, when the outside temperature changes, the scan tool will display the change of the input status of the outside air temperature sensor. Use this kind of information when diagnosing a malfunction associated with a particular HVAC input or an input that is shared with another system.

Use the scan tool to cycle the HVAC module output functions. When the HVAC module output cycling is selected, the scan tool can command the HVAC module to cycle an output. This feature can be used to determine if the HVAC module is able to cycle an output regardless of inputs or specific program instructions. Once a test is selected, the scan tool will command the HVAC module to energize the selected output. The scan tool will then display the status of the selected output. For example, a command can be sent to the air temperature valve sensor and motor to move to the full hot or full cold position. After the command is sent, the inside air temperature valve sensor and motor will send a position feedback signal to HVAC module indicating its movement. The displayed information represents only what was commanded, not the action which actually took place.