A periodic smog check is just a part of life for most drivers, costing about $30 to $50. However, some drivers were paying up to $200 for shops to cheat on the results.
A video from the Bureau of Automotive Repair shows how a technician would swap the readings from a known clean car for one expected to fail. It's known as clean piping and it's a felony.
"That's just flaunting the clean air rules that we're trying to enforce and that we all care so much about," said Santa Clara County District Attorney Dolores Carr.
This is one of seven smog shops where owners and technicians were convicted of tampering with the results. This shop is under new ownership.
The state crackdown also caught five other San Jose shops, one in Morgan Hill and one in Santa Clara.
Smog technicians who obey the regulations said they're pleased with the enforcement action.
"We have to go to school, so we know what the consequences if you do cheating," said certified smog technician Huy Mai.
The cheating was detected because the smog machines relay unique codes to Sacramento.
"Those codes are for certain makes of cars typically, and so if a code is not on this make of car, that's an easy trigger for us to see that it's not the car that's being smogged," said Sherry Mehl from the Bureau of Automotive Repair.
Van Bui is the new owner of one of the seven shops cited. Customers keep showing up, asking him to cover up when they fail.
"They just ask me to pass their car, and I'll say, I can smog it, and I can't guarantee anything," said Bui.
The District Attorney's office says the customers knew exactly which shops would fudge on the results, but for now, they're going to go after the owners and the technicians, not the customers.
List of smog shops facing charges:
Tram Test Only Center, Inc.
288 E. Virginia St.
T N T Smog
16860 Joleen Way #7
Santa Clara Test Only
3295 El Camino Real #H & I
Spartan Test Only
1608 Almaden Expressway
914 Test Only
914 Commercial St.
210 Smog Test Only
210 San Jose Ave. #3
Century Auto Service
331 Keyes St.
Disclaimer: Some of these businesses may have already changed hands and may be doing business under another name.