Since your Corolla is a 93, it will be equipped with OBD-I, which means you can do a diagnosis check on it yourself. All you'll need is a paper-clip or a piece of wire. Look in your engine bay and you'll see a small black box next to the driver's side strut tower that says 'Diagnosis' on it. With the paper-clip stretched out (or a bit of wire with both ends stripped), put one end into the port labelled TE1 and the other end into the port labelled E1 (the labels are found on the underside of the diagnosis box cover, much like a fuse-box). Be sure not to clean any of the grease off the connectors as it's there for a reason. Simply just poke through it with the paper-clip or piece of wire.
Turn the key to the ON position, but
don't start the engine. If your connections are correct then the check engine light should start flashing. Keep note of how many times it flashes as this is the code it is giving you. For example, if the code was 35 it would flash 3-times, have a short pause, then flash 5 more times, then have a long pause. If it repeats the same code after the long pause then that means it's the only fault detected, if it flashes for a different period of time then that means there is more than one fault. If it flashes continuously with no pauses in between then that means there is no fault detected at all (although since the check engine light is already on, there will most definitely be a fault code detected). Don't worry if you missed the code because it will keep repeating itself until you remove the paper-clip or piece of wire on the diagnosis box. Just be sure to have a pen and paper handy.
Once you've got the code, then head to this website to find out what it means:
http://www.off-road.com/toyota/tech/codes/
1993 Toyota Corolla
Linear Mode
