Snap-on Training Solutions helps you get the most out of your ETHOS Tech diagnostic tool. This training module covers the use of scanner functional tests.
Functional tests are a great way to isolate the cause of a problem between a 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 a step by step test instructions. Select continue. Select each injector one at a time to disable it and compare the RPM drop between injectors. 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. This is known as a toggle test.
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 be the relay or wiring.
In order to choose relevant data parameters to monitor use the back button to open the data menu. Select the data group, accessory, electrical theft data. Click on the checkmark icon. Let's view the data parameters relevant to the AC relay test. First use the select all icon to de-select 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
Snap-on is dedicated to helping you get the most out of your diagnostic tool and keep your customers happy. Be sure to watch the rest of the modules in this Training Solutions series.