you don't need to buy a code reader. try to find the connector like the one pictured, with the key in the off position, run a paperclip from a to b and turn the key on. The service engine soon light will start flashing. Should flash code 12 first- one flash followed by two flashes. Should do that twice than flash the code that originally is the problem, the one I had last I think was a code 15 for the ect. Than it will flash code 12 again when it's done.
The aldl connector should be on the drivers side under the dash.