Originally Posted by Wheelman
you dont need a tool just jump the two terminals next to each other on the obd port with a wire or paper clip. Then turn the key on and off 3 time the last time leaving it in the on position the last time. Then count the flashes on the check engine light. It will blink a few time then pause then blink again. Like Blink,Blink, Pause Blink,Blink,Blink and that would be 23. It will repeat the code 3 times.
I tried to do this the other day and it didn't do anything. This only works on OBD1 ports that have a terminal in both the A and B slots, mine doesn't. This is why I was looking for a scan tool.