Welcome to Snap-on Training Solutions. This module is designed to help you get the most out of your MODIS Edge diagnostic tool, and covers the use of scanner functional tests.
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
Select the Injector Balance test
The next screens give us step-by-step test instructions. Select Continue.
Select each injector one at a time to disable it.
If you are using a fuel pressure gauge in conjunction with the test, compare pressure drop between cylinders.
Select an injector once to deactivate and again to activate.
Output Controls
Actuator Tests
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.
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. Click on the checkmark icon.
Let’s view data parameters relevant to the AC Relay Test. First use the Select All icon to deselect all parameters.
Select just the parameters you want for your diagnosis. To perform the AC Relay test we will select AC-related data.
This will speed the data refresh rate to help you catch short intermittent glitches. Here's your Custom Data list. Now you can observe the vehicle data response when you command the AC Relay On and Off.