California Does It Again – Modified ECU’s Will Now Fail Emissions Tests

California, what’s going on? As the Golden state focuses its efforts on reducing pollution, which still ranks among the highest in the country with 90 percent of Californian’s breathing unhealthy levels of air during some part of the year, more rules went into effect that make the smog process even more challenging if you have a modified car. With that said, it shouldn’t come as too much of a surprise as it was passed in 2010 under Assembly Bill No. 2289.

If you’ve never been to California and your city doesn’t make you jump through hurdles to get your yearly registration, the term “Smog Check” refers to an emissions inspection. While some counties implement this throughout the United States, the one in California is notably stricter. It uses a “sniffer” test to weed out any pollutants from your car’s exhaust, among other visual inspections, and the state has taken it up a notch by going after “unapproved” ECU software. Tests will be done to see if the files have been altered in the ECU through a CVN (Calibration Verification Number).

So, what does this mean exactly? California’s emissions tests are specifically targeting modified engines, and if you’ve made changes to the software or coding of your ECU, you’ll fail. With enough data points, smog shops can determine if your car doesn’t match a profile within a certain degree of error, meaning it’ll know if you’ve modified the ECU. According to the CA.gov website, “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.”

Before your car can pass a Smog Check, the vehicle’s software MUST be restored to the OEM version. You can do this by flashing back to your original configuration and ensuring all your OBD readiness monitors are reset. Once restored, you can bring it in for inspection. If you unknowingly purchase a car with illegally modified software, you have the option of filing a complaint with BAR. If your vehicle has CARB-compliant upgrades, you’ll be in the clear.

What does this mean for California’s robust car culture? It could be significant. Many will respond with their wallets and start registering cars out-of-state, move away, or they’ll pay a fortune at shady smog stations that will illegally inspect your vehicle, which can get you in a lot of trouble with the state. Either way, the hostile nature of owning modified cars continues to grow, and the state could be driving away enthusiasts altogether.