not sure where that is located
chk engine light is on.autozone quick test said it may be the egr valve on 2004 Chevrolet Impala
it could be the egr or the circuit the valve is located on the top of eng
1 more answer , 1 more comment
That is not a common problem on that car. I would take it to an experienced repair shop and have it properly diagnosed. Autozone only "reads" the codes. The problem still needs to be diagnosed.
By coincidence they sell parts to , right? Take both of the other suggestions and get it diagnosed FIRST , before guessing on parts.