Check Engine light stays on

[stephendoherty62]

I replaced the Spark Plugs and the Polyrib Belt last night. I turned over the car and notice that one of the plugs was not firing and the check engine light came on. I check the connections and found one of the Sparkplug Wiring was not connected to the Cap, I reconnected it and the engine is behaving normal again. But the check engine light remains. Question? Once the check engine comes on, does it need to be reset? Any ideas