This is a bonus cache. In order to find the coordinates for this cache, you will need to complete the Route 66 Rialto-Rancho Cucamonga Adventure Lab. The coordinates are going to reveal themselves in two of the nearby stops. You are searching for a small pill bottle hidden is the most obvious spot at the final coordinates.
Use your phone's native QR code scanner to open this Adventure in the Adventure Lab® mobile app, or share the following URL:
https://adventurelab.page.link/QcAj