check engine light comes on after changing clutch? Options

[st202gt]

94 celica gt...well my engine light came on after we had finished changing my clutch... The speed sensor wire that attach to the transmassion was broken off and had to replace it with a used one that i got at the junk yard...first when i did the wire and disconnected the battery..the speed on the gauge didn't work, but the rpm work... i rewire up again and now it works....but the engine check light comes on as you start up the car... I tired to get rid of it. but it still comes on when you start the car...I think it the wire that is moving around to cause for that to happend or some other thing....I really need help or advice about this...because i need to smog my car in oct.

[Delta_Phoenix]

you can do a diagnostic check of your CEL. check this page for instructions. i forgot exactly where it tells how to do it. you have to use a paper clip or some other piece of metal and bridge 2 of the pins in your diagnostic box under the hood. the site lists the codes and all, so you should be able to figure out what's causing it pretty quickly. i'll look for it and get back to you with a direct link to it.