Snap-On S-40 Personality Key

The Snap-On S-40 Personality Key is a specialized diagnostic accessory that tells a Snap-On tool which vehicle communication profile to use, enabling OEM-specific tests and data access on supported makes. It is part of Snap-On’s Personality Keys lineup and appears in older catalogs as one of the European keys, grouped in bundles such as Bundle 10.4 alongside S-25, S-43, S-44, S-45 and S-62; the bundle notes Land Rover as a commonly supported make, indicating the S-40’s role for vehicles in that market segment. When installed in a compatible Snap-On diagnostic platform, the S-40 switches the tool into the correct protocol for the vehicle, enabling model-specific diagnostics and access beyond standard OBD-II. Like other Personality Keys, it is designed to be used with Snap-On diagnostic systems and is typically ordered through a Snap-On franchisee. In practice, the S-40 is used in service workflows where a vehicle requires a manufacturer-specific interface to access certain tests, coding, or data that are not available through generic diagnostic modes, making it a targeted part of the Snap-On keys ecosystem for European makes such as Land Rover.