Functional

Functional Tests

The Functional Tests selection is used to access vehicle‑specific subsystem tests. Available tests vary by manufacturer, year, and model. Only the tests available for the identified vehicle display in the menu.

There are several types of functional tests:

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Information Tests—these are read-only tests, like selecting “VIN” from a Functional Tests menu to display the VIN of the identified vehicle.

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Toggle Tests—these tests switch a component, such as a solenoid, relay, or switch, between two operating states.

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Variable Control Tests—these tests command a certain value for a system or component, such as varying spark timing in 1° increments or EGR valve duty cycle in 10% increments.

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Reset Tests—these tests reset the adaptive, or learned, values that are stored in the vehicle electronic control module memory.

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Scripted Tests—these tests are software routines that place the vehicle into special operating modes for performing certain repairs, such as bleeding brakes with ABS.

Selecting Functional Tests opens a menu of test options that varies by make, year, and model. Selecting a menu option either activates the test or opens a submenu of additional choices. Follow all screen instructions while performing tests. How and what information is presented on the screen varies according to the type of test being performed and the vehicle being serviced.

Functional test menu

Toggle and variable control tests often display functional test controls on the toolbar at the top of the screen with PID data in the main body.

A Test icon on the toolbar activates the test, and a Return, or similarly named, icon cancels the test. For variable control tests, the variable value displays between the main body and the toolbar. Plus and Minus icons on the toolbar increase and decrease the variable value.

Data List icon, is available on the toolbar for some tests. This feature allows you to change which data list displays in the main body without exiting the functional test. The icon is only available when the test is inactive.

See the following examples of functional test screens:

Functional test example