Why is my 01 Pontiac Grand Am gt v.6 check engine light on?

[LADY4EVER]

Hi all

My car Need a NY State Inspection . The auto shop change the following:
EGR Valve
CHANGE OIL
PCV VALVE
THERMOSTAT
filters
wires & plugs (Adelco)
After the above change only the left service engine light is on


Thanks much for your replies.

 

[The Wiseman]

He did not replace your oxygen sensors, one is bad or all