WARNING: This page is about a different car, the 2020 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.
Courtesy of MAZDA MOTORS CORP.
Connection terminal: 2D (+) ↔ body ground (-) 2F (+) ↔ body ground (-)
Oscilloscope setting: 2 V/DIV (Y), 1 ms/DIV (X), DC range