A method of controlling an automotive computer comprising the steps of: providing control signals to an engine from a first computer, said control signals comprising engine operating parameters; providing at least one originally provided programmed mode for operating said engine from at least one originally provided memory coupled to said first computer; communicating a superseding signal to a bus coupled to said first computer and said at least one originally provided memory through a diagnostic/emulation port or harness coupled to said bus from an adapter module, said superseding signal to alter control of said engine by said first computer; selectively controlling said engine by means of said first computer through at least one additional programmed mode provided by said adapter module, said additional programmed mode not being originally included in said originally provided memory. view more