California Will Start Failing Vehicles During Smog Checks if the ECU Has Been Tuned


California Will Start Failing Vehicles During Smog Checks if the ECU Has Been Tuned

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California just became a tougher place for car enthusiasts to live.

The California Air Resources Board has instituted a new policy for Smog Checks beginning July 19, 2021 that will mean cars not running the factory software or a CARB-approved tune will fail the test.

According to CARB:

Before your vehicle will pass a Smog Check, you must have the vehicle’s software restored to the OEM software version. Once the software is restored, have your vehicle reinspected by a licensed Smog Check station. If you believe the vehicle’s software is already OEM or CARB-approved and yet your vehicle failed Smog Check, schedule an inspection with the Smog Check Referee. If you unknowingly purchased a vehicle with illegally modified software, you may file a complaint with BAR.

We heard about this new policy in a post this week by Road & Track, who say tuning your car is one of the easiest and most effective mods you can do to a car, one that often provides measurable results, especially if the car in question is turbocharged.

Since California has long had tough emissions policies, this latest policy is right in line. While the number of cars affected is likely to be low, apparently the state believes there are enough of these vehicles that are increasing emissions enough to try and keep them under control.

One person responding to the Road & Track post suggested the following compromise:

I say challenge the tuner to achieve power and efficiency without increasing emissions just like manufacturers do to get their cars sold in California. Probably only the biggest tuning shops will invest in CARB-approved tuning, but would be a good balance of performance and environmentalism. Another solution would be to exempt those vehicles that do less than x miles per 2-year cycle. Maybe 10000 miles?

We wonder just how effective this policy will be, since it’s likely that owners will switch their cars to OEM settings for the few minutes of testing, then just switch it back once they get home. How will that do anything to save the environment?

What’s your opinion of this new rule?


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  1. Lived here all my life, can’t believe the CRAP coming out of Sacramento, we MUST wear masks, while the Gov eats @ the French Laundry with out a mask. Also, our kids can’t go to public schools “for their protection” while his never missed a day @ private schools. TOTAL hypocrisy. This is just more virtue signaling by the Godless Left.

  2. I think its a great rule. If all the CA, OR and WA cars were required to be cleaner, the rest of us living east of the left coast won’t have to breathe all their dirty smog.

  3. Good for sales of portable tuners like the Diablo I3. Have the stock and custom tune stored so I can switch back and forth as needed. Don’t worry the EPA is working on Common Sense car laws with background checks. Heck they may even merge with the ATF for enforcement help.

  4. Ya well that’s California for ya. Cars are cleaner then ever these days. CA is becoming the “shit hole” of the SW. Hey Billy boy, shut your pie hole and go wash your friggen Prius. And BTW Portland area already has DEQ stations. OR and WA has great air thank you very much.

  5. Here is more info:
    Department of Justice consent decree states: “According to the schedule outlined in this Paragraph, Defendants shall not manufacture, offer for sale, sell, convey, or otherwise transfer any product intended for use on vehicles of model years 2000 and newer that contains user-adjustable features for the following: rear oxygen sensors, EGR, or any DTCs associated with these emission controls. Defendants shall remove these user-adjustable features from any of its Calibrations intended for use on vehicles of model years 2000 and newer prior to sale by the following dates: no later than June 1, 2019, for all of their Calibrations compatible with any Ford vehicles; no later than December 1, 2019, for all of their Calibrations compatible with any General Motor (GM) vehicles; and no later than August 1, 2020, for all of their Calibrations compatible with any other vehicles.”

    What I read is that you can still tune your vehicle, but you will no longer be able to turn off sensors or set DTC’s

    Good for you if your tune doesn’t trip a DTC or check engine light.

  6. 2045: We will all be driving electric Corvettes.
    Except for Kevin: They’ll be trying to pry his fingers from the steering wheel of his C4.
    But at least he will have an oil rig in his back yard so he can pump and refine his own — since energy companies will no longer be in the oil business.

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