I couldn't remove the CCV from the rubber fitting, how can I pull out those CCV without damaging the rubber fitting? There are two CCV valves, both can not be pulled out, you can turn them around but can not be pulled

How difficult is it to replace the oxygen sensor, does the engine needs to be hot? the Diagnostic Trouble Code indicates the oxygen sensor.

Any idea?

What's the CCV?

Spray the old oxygen sensor with PB Blaster or Kroil (let it sit for a while), spray with PB Blaster or Kroil again, warm-up car for several minutes, and use a 15-inch breaker bar on the end of a 22 mm oxygen sensor socket to remove sensor. Afterwards, clean threads thoroughly with brake cleaner, allow to sit for quite a while and "air out," and install new oxygen sensor with anti-seize compound. Good cleaning technique is a must. Tighten to 33 lb-ft or 4.5 kg-m.

I am not a fan of universal oxygen sensors or those made by Bosch. I recommend OEM sensors. Over time, you want the best sensor or you will pay for it in poor gas mileage and performance. Oxygen sensors are EXTREMELY sensitive to anything, particularly silicone spray, RTV sealers, WD-40, or any oil on the pigtail connector. Don't even use non-chlorinating brake cleaner or electrical contact cleaner on oxygen sensor connectors. NEVER use any of these products around the oxygen sensor or pigtail connector. If you do, the ECM will keep throwing a code forever, once the engine warms up and is out of "open loop" mode. Remove pigtail connector and gently dress the male and female connectors with jeweler files, if you suspect any contamination.

CCV (Crankcase Ventilation), works the same way as a PVC (Positive Crankcase Ventilation)

CCV (Crankcase Ventilation), it is the same as a PCV(Positive Crankcase Ventilation

Sorry, I posted on the wrong post to answer your question. " What is CCV"
The CCV is the Same as PCV, CCV stands for Crankcase Ventilation and PCV is Positive Crankcase Ventilation, no idea why they use a different name.

Some PCV valves are 180 degree twist-threaded, with O-rings on them. Old, crusty oil sometimes makes them difficult to remove.