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APOLLO-D8 Training Module 6

Applies To: APOLLO-D8™

Functional Tests: Scanner Functional Tests, Scanner Output Controls, Bi-Directional Controls, Actuator Tests, Custom Data List



Welcome to Snap-on Training Solutions. This module is designed to help you get the most out of your APOLLO-D8 diagnostic tool and covers the use of the scanner functional tests. I’m Jim Moritz, Global Field Trainer, and Sales Support Representative.


Functional Tests are a great way to isolate the cause of a problem among the controller, a component, wiring or other issues. Functional tests let you override the vehicle controller to take control of a system and determine if the vehicle responds properly or not.

From the Main Menu select Functional Tests.

The available tests are listed. For this example, let’s choose “Cylinder Power Balance”.

This test allows you to turn individual injectors on or off. Let’s choose Injector #3.

The tool will show any precautions or preparation steps before beginning the test.

Press the control at the top of the screen.

Choose “Yes” to disable the injector.

You can see the status of the injector on the screen. You can then view the data and also see if the vehicle’s idle changes.

Select “No” to turn the injector back on.


Other useful types of functional tests are Actuator Tests which check operation of devices like solenoid valves, motors and relays. And Output Controls, which monitor live output data from the vehicle while you activate vehicle components.

A good example of a powerful Output Control is the AC Relay Test.

Select the test and the AC Relay control shows at the top of the screen, and the live data parameter view opens.

Press the button to begin control.

By using the functional test and selecting ON, you are overriding the controller.

If you command the relay to turn ON and it does not activate you’ve just eliminated the controller from the possible causes. This pinpoints the likely problem to the relay or wiring.

To change the data that is on the screen, press the “change data list” icon.

Select the data list you would like to see from the list.

The chosen data list is displayed.

Last Updated: July 2, 2020

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