[1990TS]

Jumper terminals A and B together, they usually have a slot in the plastic connector between the two and are located on an end. Yes they made a key for these, but you could use a paper clip too if need be. The ignition key has to be in the run position with the engine off. The service engine soon lamp should flash a code 12 three times, then flash any other stored codes three times, then back to code 12. You really should pick up a service manual for your car that explains how to do the diagnostics. Because once you pull any codes, you'll still need the rest of the info to do a proper diagnosis and not throw parts at it unnecessarily. If you have not seen the check engine or service engine soon lamp on recently while driving, most likely there will not be any codes stored. Anyway, after you check for dtc codes, you will still most likely need to do regular diagnostics, like fuel pressure, exhaust back pressure, etc... All the stuff that caused lack of power 50 years ago is still basically there today and still needs to be checked. I bet Autozone will not be able to pull your codes as this is an older car that they most likely don't have the software for and most likey don't have a 12 pin connector for the scan tool. Just a guess, I could be wrong.