2000 Saturn SL2 won't pass smog test

Take it to a qualified repair shop an have it fixed

Because you failed to have a shop look at the data
& make the required repairs & get caught up on preventative
maintenance BEFORE you went to inspection

If you were in fact at a shop, for any reason,then they have no idea
how to test vehicle

Have you considered the motor is shot & you have leaking valves?

Just because the car seems to run well, does not mean the emissions are within spec. For example, you could be running a little rich and the car will start and run great, but the exhaust is not within code.
What you can do is take it to a "smog shop", that is a repair shop with the proper equipment to diagnose the problem. If the testing is simply the reading of the on board computer codes, then most any place can read those, but you need an experinced mech to know what to do about it. May need an exhaust gas analyzer to physically sample and analyse the gasses. For the actual test, as long as the computer says all is fine, usually, you're good to go.
If the computer looses power any saved run data will be lost and must be re-accumulated to pass the smog test. A few hours to a day is usually enough run time to accumulate enough data.

Find someone with "VAGcom" or VCDS cable and software.

good luck.

Replace the head gaskets. It would have passed the smog test, because oil and water are not getting in to the cylinders.

change your O2 sensor.

Some vehicles require very specific drive cycles (called "drive traces" if you perform them on a road simulator or dyno) to activate certain self-checks like the catalyst and EVAP monitors. As a general rule, doing some stop-and-go driving around town at speeds up to about 30 mph followed by five to seven minutes of steady 55 mph highway speed driving will usually set most or all of the monitors. Consequently, if you're checking an OBD II system and discover that one or more of the monitors have not run, it may be necessary to test drive the vehicle to set the remaining monitors.

You should talk to a good emission tec, if this is not throwing a code, it is hard to say if that one of the components could be bad. O2,pump,convert, HeO2, every part of the emission system.

With a 1000 miles, and doing what is says above just before the test, and ending driving at the test
should be plenty. If it is not, you will have to have each emission part checked, or when the computer
is plugged in it might show a code that did not trip dash light.

Change the oil, run the car until it is really hot (the cat converter) and it should pass, did smogs for 30 years, this usually works.

the no data error can be contributed to a bad interface cable or the scaqn tool was configured wrong and therfore could not connect to the ecm. I would recommend having a scan done again by a certiefied volkswagon tech chances are the mechanics used the wrong adapter cable or reader card. your smog problem could be that your evap canister is clogged therfore gives a bad reading.unfortunately you have to have a scan done but try an independant small shop that delas exclusively with foreign cars such as porche andd mercedez. the will have the correct scan tool and will be much cheaper than a dealership. your cost should be no more than 50 dollars US ... please rate this. thanks