The Smog Shop was established in 2004 to fill the need of a highly trained and friendly smog check station in the concord area. Since then we have done thousands of smog checks and built up a loyal following of happy customers. We are a test only center so we are a completely unbiased when it comes to performing your smog check, which means no failing vehicles to get unnecessary repairs, because we are not allowed to do repairs. We have become Star Certified in the fall of 2012, which means we have been recognized by the state of California as being a top performing smog check station. This certification allows us to perform smog checks on Star Certified directed vehicles.. The Smog Shop is a Star Certified Test Only Station located in Concord,CA. We perform smog checks for Star Certification,Test Only,Change Of Ownership,Biannual Registration,Salvage Title,Diesel,and Gross Polluters. We provide a free retest and the paper work for financial assistance in case of a smog check failure.