Nope, it's all mechanical injection. Disconnect the vacuum hose to the shutoff valve, turn off the key, and you'll see what I mean. The idle speed is controlled by the computer, but that's just about it on the fuel side. The computer also controls the turbo boost and will cut boost when it sees a problem somewhere. It will not prevent the car from running.
To pull the codes, you need to build a simple circuit with $20 of parts from Radio Shack.
Schematic here (go to bottom of page). Take the cover of the diagnostic connector near the positive post of the battery. Plug the test lead into port 4, and the ground into port 1. Then connect the +12V lead onto the positive terminal of the battery. Press the button for two or so seconds; the LED will flash a number of times. I can get the referece page if you need it so you can know what they all mean. After reading and writing down a code, hold down the button for 8-10 seconds to clear it. Each code must be cleared individually. A single flash means there are no fault codes stored. With the engine off, you'll always get a code 9.
Not sure if the head is interchangable. I would guess not as the engine numbers were different. Although I seem to remember seeing somewere that the 603.970 heads work on 603.96 blocks...so I'm not positive.