IDonT said:
You also have to take account teh censor suite of PLAN's deisels. Can they detect the US subs?
Sure they can.

Depending on where the US subs are and what they're doing/ how fast they're going.
About locating the carrier... it's much harder to do it in the open sea, where we have two fleets and they're both maneouvering around each other etc. If US and china would do battle chinese wouldn't go out to find and get the carrier. The burden would be on the americans to get close enough to china/taiwan to be able to attack chinese ground forces/navy or offer air protection. Being close enough to do that, the CBG gives the chinese a comparatively much smaller area to search. Not only that but operating from the mainland, chinese can use their overwhelming numbers to pinpoint the location of the carrier, of course losing not a small number of units while doing that.
After that it's anyone's game. One or two CBGs could not stand against fully determined to win at all cost combined chinese navy and air force attacks. But lets say that does happen, PLAN and PLAAF would be left rather weak after those 'successes'. So, ultimatively, if the US is fully comitted to the war, USN and USAAF would fully defeat their chinese counterparts in the long term.