You can reset by clearing the codes, for one.
Pull the ECU from under the dash, at the center console. There's a screw located on the rear of it, on the same side the harness is.
Turn the key to the on position, and then turn the screw with a screwdriver fully counter-clockwise, wait for 3 seconds, then turn fully clockwise. Look at the dash and the check engine light will blink
One long light = 1, two long lights = 2 and so on. Followed by short lights. 1 short = 1, 2 short = 2, etc.
You would read them as such: 5 long, and 5 short = 55 (no faults.)
Read your codes and report back what they say. (25, or 34, 37, etc.)...
To clear the codes, turn the screw counter clockwise fully again, and then back clockwise fully. You can then turn off the ignition, and then start the car back up.