You read the codes with a scanner, repair the cause, and clear the code with the scanner.
use an OBD-I code reader.
pepboys.
www.troublecodes.net Good luck I have a 1995 jdauksz1@charter.net
Click the link for directions and a diagram.
http://www.extreme-check-engine-light-codes.com/Toyota%20OBD1%20Decoder.htm
To check engine codes on a 1995 Geo Prizm, you need to locate the diagnostic connector under the dashboard, typically near the steering column. Use a paperclip or a jumper wire to short terminals TE1 and E1 on the connector. Turn the ignition key to the "On" position (but do not start the engine), and the check engine light will flash the trouble codes in a sequence. Count the flashes to interpret the codes, which can then be referenced in a service manual for diagnosis.
http://www.obd-codes.com/
After 1995, an OBDII scanner is necesary to read the engine codes. If you do not have access to a scanner, you can take your vehicle to AutoZone and they will scan ffree of charge.
take postive side of battery off then put back on
All 1995 and later model vehicles require an OBDII scanner tool to retrieve the trouble codes.
Check the codes with an OBD2 scan tool.