New California Smog Test Will Fail Tuned Cars

Industry News / 17 Comments

The updated test went into effect this week.

Introduced way back in 1984, the Smog Check Program in California has successfully reduced pollution levels in the state by identifying offending vehicles that are either too old or need to be repaired. It's not unusual to find used vehicle ads in that state specifying proof that the smog test has been passed.

However, a new amendment to the requirements of the test was introduced on July 19, 2021, that will affect owners of ECU-tuned vehicles. Vehicles with a tuned ECU will automatically fail the revised test, although this doesn't completely spell disaster for tuner-friendly cars like the Chevy Corvette, Mazda MX-5 Miata, and Toyota 86.

The official California state portal says the following: "Beginning July 19, 2021, vehicles with software not provided by the original equipment manufacturer (OEM) or approved through a California Air Resources Board (CARB) Executive Order (EO) will fail Smog Check."

According to the state government, modified cars can simply be restored to their OEM settings before getting a smog test. Once passed, owners will receive a smog certificate valid for 90 days and it's up to them to decide if they want to re-tune their vehicles. Owners who unknowingly bought a modified car that fails the new smog test may lodge a complaint with the Bureau of Automotive Repair. So, more than anything else, the new rule has created an extra bit of admin for owners with modified ECUs in their vehicles.

2016-2021 Mazda MX-5 Miata Front View Mazda
2016-2021 Mazda MX-5 Miata Engine Mazda

Whether you drive a Toyota Prius hybrid or a tire-smoking Dodge Challenger in California, every new gas, hybrid, or alternative-fuel vehicle produced as a 1976 model year or later requires a smog test. However, there are some exceptions, stipulated below from the California state website:

  • Eight model years and newer do not require a biennial Smog Check
  • Four model years and newer do not require a change-of-ownership Smog Check

The regular smog check test still includes a visual inspection, an inspection of tailpipe emissions, and an inspection of the on-board diagnostic system. The new rule may be a frustration for some, but then again, with California's move to ban the sale of gas cars by 2035, smog tests won't need to be around for much longer.

2015-2017 Dodge Challenger SXT / GT Front View Driving Dodge
2015-2017 Dodge Challenger SXT / GT 3.6L V6 Engine Dodge
Source Credits: California State Portal

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