The present invention provides a systematic means of switching contiguous segments of each production-test shift-register into several diagnostic scan-configurations. The SRAM environment circuitry is operable to interface with external asynchronous circuitry and to enable reading of and writing to the SRAM state elements in a delay-insensitive manner. The method also includes determining a number of vehicle operating points during a second braking event when the vehicle is towing the trailer; determining a current brake operating point; and determining a trailer brake command signal based on at least the first relationship, the M vehicle operating points, and the current brake operating point. The threaded portion includes a thread having an outer diameter. An aspect further includes receiving, at the server computer, a request to access a network resource that includes the access token, invalidating the refresh token, and providing the client device with access to the network resource.