Yes, the crank sensor code is code 12, and I'd start with simply verifying that the sensor is good.
If you look in the nose of your sled next to the voltage reculator, you'll see a 2 wire set of connectors with a grey and black wire to them. It will be coming out of the harness right with the heavier wires to the regulator. Try checking those for any corrosion first. If simply cleaning that plug doesn't help, try this
Using an ohm meter on the crank sensor plug (I believe it's the black plug of that pair) connect your positive tester lead to the grey wire, and negative to the black wire and read the ohms. It should read between 445~545 ohms. If it doesn't read between that post your results and we'll go from there. It's possible that your sensor needs adjusted to the proper gap to the stator wheel, or the sensor is faulty. If it's faulty, I can help you find another one.
The dealer may be telling you that if it's only available with the entire stator cover, but there's other options if you need it. I know it's not your computer since it's actually reading the sensor and telling you that it's not getting the correct signal from it, which is what the code 12 is. If the ecu were bad, you'd have an ER-"x" showing on the screen and it wouldn't be doing anything. Of all the people who post that they've changed their computers, Im pretty sure they've all ended up solving their issues with something else. The computers are pretty rugged, and are rarely the cause of a problem.
