Infallibility

Is the Catechism infallible?
What parts are infallible?
Are we as lay faithful required to obey all pertinent commands? 

  An answer offered by Brad Klingele, diocesan coordinator of young adult ministries...

The Catechism contains many quotes and various sources, so it's not as though it's "just" pronouncements.  The Catechism has many infallible portions. There are levels of authority to the Catechism based on who said what.

  Infallibility in the strict and full sense is applied to Conciliar and Papal teachings - and these would always be rather short and specific formulae.  The CCC contains many such things, but you would never have a text of book length described as infallible in its totality. From a council, a statement is infallible if it was a solemnly defined doctrine. If a Pope pronounces something on either faith or morals in a definitive manner it is considered infallible. If a pope says something from the chair of Peter on faith or morals to all of the faithful, it is considered an infallible statement. There are other high levels of pronouncements that have great weight, but these two are the biggies.

One can also argue that if it has been the self-understanding of the Church in practice and prayer, it may not need to have been solemnly defined to be infallible. Then Cardinal Ratzinger, now Pope Benedict XVI stressed the importance to obey the Church and basically not to quibble about 'levels' of authority in statements. The CCC as a whole is part of the ordinary magisterium of the Church, and as such even the non-infallible points are to be received by the faithful with "religious assent." In short, the Catechism is the teaching of the Church and should be understood to have authority for our lives.   See CCC 892 below:

  892 Divine assistance is also given to the successors of the apostles, teaching in communion with the successor of Peter, and, in a particular way, to the bishop of Rome, pastor of the whole Church, when, without arriving at an infallible definition and without pronouncing in a "definitive manner," they propose in the exercise of the ordinary Magisterium a teaching that leads to better understanding of Revelation in matters of faith and morals. To this ordinary teaching the faithful "are to adhere to it with religious assent" which, though distinct from the assent of faith, is nonetheless an extension of it.