Unless the smog technician during the last inspection conduct a smog failure diagnosis, there would have been no way of knowing for certain whether your Honda's catalytic converter was defect then, and even less likely that that assumption hold true in 2017. The catalytic converter only works well when the rest of the emission systems are functioning properly. Air to fuel ratio must be 14.7:1 in order for the CAT to reduce HC, CO and NOx from the exhaust stream efficiently.
Using Chevron Techron is great to help clean carbon deposits from your engine's combustion chambers and also to clean intake passages, but it is not a guarantee to help pass a smog inspection, especially when it is unknown which particular engine emission system may or may not have a fault. You can use the additive (a couple of times) before your smog test, but we wouldn't rely on it being the cure for any particular engine problem, most definitely not a replacement for a catalytic converter repair. If your Honda Accord barely passed the smog check back in 2015, the smog technician more than likely mentioned it'll take a new CAT to get the car to pass in 2017 because usually replacing the CAT masks high emissions problems. Consider the CAT to be a harmful emissions filter.
We'd recommend you simple maintain your vehicle properly and have the smog test administered. In the unfortunate event the vehicle fails, obtain a hands-on and thorough diagnosis from a reputable smog check repair center. Make repairs necessary.
posted by SmogTips Support
