I would address the EGR codes first. DTC 332 can be caused by a bad DPFE sensor, or else something like clogged EGR nostrils or blocked hoses.
I agree with Rockledge, begin with checking the EGR systems DPFE sensor, as it's a common failure part & seeing as how you also have a lean O2 sensor code, to go along with the EGR system operational trouble codes, you may have more than one EGR system problem, so I might also consider taking a real close look at the EGR's vacuum control system network, for leaks.
So on your trouble shoot, maybe consider backing up all the way to the EGR's VSV (Vacuum Switching Valve), to check it's diaphragm for leaks, then it's vacuum lnes all the way to the EGR valve & the EGR's diaphragm for leaks, along with the DPFE sensor & it's vacuum lines.
The code 538 suggests you didn't punch the gas pedal far enough on the "throttle up" portion of the KOER test, that checks the TPS sensor, so I wouldn't worry about it just now.
Just some more thoughts for consideration.
Let us know what you find.
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