Whoa, I was way off.

If you notice the trend, there are no "zero" digits in ECU codes. How are you reading codes? Here's what I suggest:

I'm assuming that you've found the potentiometer (screw thingy) in the side of the ECU. With the key in the 'off' position, it should be all the way counter clockwise. Turn the key to 'on', turn the potentiometer all the way clockwise, count to 3 and then counter clockwise. The LED next to the potentiometer will blink out the codes.

If this is what you're doing, something funny is going on. Take it to Autozone, and they can read your codes through the consult port.