Just to add on to this (because I think it's interesting)... the Engine Computer (PCM - Powertrain Control Module) does so much! Just to name a few: - Coordina

Just to add on to this (because I think it's interesting)... the Engine Computer (PCM - Powertrain Control Module) does so much! Just to name a few: - Coordinates the engine and the transmission for smooth shifts - Holds a gear while the engine is in the power band if the throttle position meets a certain threshold - Makes diagnosing complex problems much easier, even remembering data so it can be diagnosed when the problem is not happening at the time you drop your car off with a technician - Shuts the engine and fuel pump off if it receives a message on the vehicle bus that an airbag was deployed - Can advance or retard ignition timing depending on the grade of fuel you put in the tank - Reads/Adjusts combustion parameters thousands of times per second on each cylinder (prioritizing fuel economy, power output, and emissions depending on the situation).