
Originally Posted by
12vdc
ECU may mean Electronic Control Unit w/c is a computer box controlling a specific part of the vehicle. Older vehicles usually controlls only the engine hence they call ECU as Engine Control Unit. Newer vehicles have separate computer for Engine management, Powertrain, Body Control, Airbag, Transmission, Suspension, etc.. Like a computer, all these control units communicate thru a common bus. Each units could be pre-programmed, run an application specific code, self-learn from the user behavior thru the map.
Fuel injected engines w/c do things like ignition timing advancement/retardation, air fuel mixture, etc.. is controlled by ECU or ECM (Engine controll unit/module).