[RoyGBivCap]

I wish I'd known this. Oregon's bi-annual "emissions test" where they hook up the inspection machine to the ODB port and let the car lie to it is absurd. When I first heard about it I assumed they'd put some device on the exhaust. They do not.

[winrid]

CA is the same way.

I really wish it was tailpipe based. I liked the PA emissions laws where you could improve the efficiency of your vehicle and it would pass. Not so in CA, must be numbers matching and CARB certified parts/combo.

[quesera]

> I assumed they'd put some device on the exhaust

They used to do it that way. Still do, for some cars, although the pre-ODBII set is now out of smog regs in most states.

Turns out the tailpipe breather machines are finicky and difficult to calibrate, causing false positives and false negatives (sometimes corruptly).