California divides smog stations into two main groups, "Smog & Repair Centers", and "Smog Test Only Centers".

Smog & Repair Center - You can obtain a smog test at a Smog & Repair Center if the DMV states "Smog Check Required" and makes no mention of a Test Only Center.

Smog Test Only Center - You can obtain a smog test at a Smog Test Only Center anytime your vehicle needs a smog check without any repair, or when the DMV states "Test Only Center Required".

Gold Shield/CAP Smog Center - CAP stations are licensed "Test and Repair" stations which have been certified by the Bureau of Automotive Repair to perform repairs on vehicles participating in the California Consumer Assistance Program. Please see CAP station definition below.

Why are there three station types?
California is continuously improving the smog check program. So far this method of process has proved positive in terms of air quality. State research has shown Test Only stations to provide a MORE accurate smog test then their counterparts. For this reason, vehicles with high emission failure rates are directed to Test Only Centers.

STATE OF CALIFORNIA SMOG STATION DEFINITIONS

Test Only Centers - "Test Only" stations, as their name suggests, can only perform
smog inspections and are NOT allowed to perform any repairs. A Test Only Center's main obligation is to insure a non-bias and accurate smog inspection.

Test & Repair Stations - "Test and Repair" smog stations are licensed by the State of California to provide smog tests and repairs to vehicles requiring OTHER THEN Test Only inspections - otherwise known as the "regular" smog check. Under the current law, "Test & Repair" stations are prohibited from inspecting vehicles directed to Test Only Centers.

Gold Shield / CAP - "Gold Shield/CAP" stations are also licensed "Test and Repair"
stations, however these particular stations have been certified by the Bureau of Automotive Repair to perform, along with "regular" smog repairs, repairs on vehicles participating in the Consumer Assistance Program. CAP Stations must maintain a high standard of operation.