I just picked up a '93 SSE. It wasn't running, sat in a driveway for about 1.5 yrs. I cleaned it up, 1st step, changed the battery. I pulled the codes, 12 and 42. Security light stays on solid.

I'm thinking of changing out the coils, wires, and spark plugs.

(I HAVE read around here that the ICM or PCM may be bad, but I believe there would be different codes if the PCM was failing. The previous owner reported some rough running/shutoffs that lead me to believe the coils and/or ICM are gone.)

Any more advice to proceed? Thanks in advance for any help you can give.

Okay, I figured out that 12 just means its in diagnostic mode (D'OH!)

code 42 cleared by changing out the ICM. I picked up an ICM (with coils) from a '98 at a junkyard, but the coils test out a 8.3kohm, while my original coils were like 5.75kohm. Is that gonna be a problem? If it is, I'm in for buying new coils, since my two of the old three coils have screws that are rusted to the bad ICM - meaning, un-removable. Shame, since they all had "good" readings (I'm assuming 4-6kohm is the range for the series 1 L27 coils)

Now, sun went down, and tomorrow I'll be checking all the new coils for spark, as the car still won't turn over. I also picked up a new set of plugs and wires, so we'll see if that does the trick.