P0420 on 2020 TOYOTA Tacoma

“The latest test I did showed the data from sensor 2 downstream, but not sensor 1. Sensor 1 showed nothing (0.0 volts) from the OBD Link MX+ whether driving or sitting still. 275,000 miles.”

“If cheap aftermarket (particularly from Amazon / ebay ) it wouldn't surprise me at all if it's shit. If you have no exhaust leaks 95% of the time it's a failed converter, O2 and AFR sensors are rarely the cause of a P0420/430.”

“Came back with code P0420 and what the title states. I replaced my catalytic converter and entire exhaust system at 151,000, and I’m currently at 154,000.”

“I want the car to run right so I’m curious how I should resolve this. I’m leaning toward replacing the entire exhaust system after the first o2 sensor and adding a cat back.”

“I would start by replacing that sensor. But if the air/fuel ratio has been too rich for too long that will easily damage the catalytic converter(s) and also result in the P0420 so it may be that you need new cats at this point.”

“Been chasing that check engine light for about 6 months. CEL will reset if I pull off the negative battery terminal, but the CEL comes back after an hours driving at highway speeds.”

“P0420 code but no cat I was looking into the usual suspects to resolve a p0420 code and discovered that my car doesn’t have a cat. my exhaust is pretty much brand new installed by the previous owner so I’m conflicted about what to do. since the trucks over 25 years old in my state I don’t technically have to have a cat to pass my inspection.”

“But if the air/fuel ratio has been too rich for too long that will easily damage the catalytic converter(s) and also result in the P0420 so it may be that you need new cats at this point.”

“Catalyst System Efficiency Below Threshold Bank 1 Recently a check engine light as well as the slip light appeared on my dash.”

“OEM or cheap aftermarket? If cheap aftermarket (particularly from Amazon / ebay ) it wouldn't surprise me at all if it's shit.”