Perform a Leak Detection Test on a Refrigerant Circuit That is Filled with Refrigerant:

-- On vehicles with a high-voltage system, switch off (deactivate) the "auxiliary climate control" function. Refer to the Owner's Manual and Infotainment/MMI Operating Manual.

-- Switch off the ignition.

-- Start up the leak detector in line with relevant operating instructions.

-- Always hold the test probe underneath the suspected leak.

Fig 1: A/C Refrigerant System, Checking For Leaks

Courtesy of AUDI OF AMERICA, LLC

Depending on the model, leak detection is indicated by an increase in clicking rate or a warning tone. Refer to the Leak Detection Device Owner's Manual.