Engine light still on

My 2005 PT Cruiser eng.light came on and took it
to a mechanic. It showed one sensor bad, replaced
it and drove 30 miles and came back on, do
replaced 2nd sensor, light came on after driving it
another 30 miles. Mechanic said a wire had burnt
and so replaced the wire and had to replace both
sensors again, but light still on. Code still the same
after repairing and replacing. We don't know what
else it can be, everything has been replaced or fix.
Please help! Need it fix by 8/1 to get it smog check
and registered. But can't get it done with engine
light still on. Any help would be appreciated.