MG and Rover dealerships used the TestBook and T4 diagnostic family also associated with Land Rover. MG Rover Group's T4 user manual identifies both MG and Rover and documents its T4 diagnostic workstation. Consult the relevant brand-specific software and model information rather than assuming the Land Rover application covers all MG or Rover vehicles. MG Rover T4 user manual.
TestBook was developed by Rover Group and Hewlett-Packard as a diagnostic and service-information system. Its Land Rover history, components and later T4/T4H references are described in the TestBook article. Hewlett-Packard history, 1994.