Since the implementation of the new STAR smog check program, smog stations are very careful in ensuring vehicles are equipped with proper/required catalytic converters.
The smog check technician will check your 2001 Volkswagen Jetta's catalytic converter EO number. If it doesn't match the required EO number as indicated on the California Air Resources Board for a 2001 VW Jetta 2.0, it will fail the visual portion of the smog check as an "emissions tamper".
The matter here indicates your VW Jetta is equipped with a D-280-54 catalytic converter, which prior to 2009 was an allowed catalytic converter for your VW Jetta. Read documention from ARB regarding EO D-28-54 Approved Jetta Catalytic Converter here.
We recommend contacting the State's smog check referee's office at (800) 622-7733. If you can prove (have verified documentation) that this particular CAT was installed on your VW Jetta prior to 2009, you may be able to have a smog check referee allow this catalytic converter.
Under new regulations a pre-OBD II (pre-2009) converter can pass the smog check as long as it was installed before 1/1/09 and you can provide the smog station proof of the installation date. The following is a PDF by the California ARB explaining the new California CAT law.
If you can not prove the CAT currently on your Jetta was installed before 2009, or if you have not owned this vehicle that long, the following ARB Aftermarket Catalytic Converter Lookup Table will show you which currently ARB approved CATs are allowed for a 2001 Volkswagen Jetta 2.0. Liter Engine.
