California smog check regulations allow for one (1) incomplete or not ready monitor, on all 2001 and new model year vehicles (such as in the case for your 2001 VW Jetta). All emission monitors, accept one (1) must be "complete' or "ready" in order to pass the smog check.
Furthermore, the Catalyst Monitor is the one monitor that must be complete if your Volkswagen the vehicle previously had any emissions defects causing that monitor not to be ready; and the vehicle is (after repairs) being retested.
