Hrddrvs

Hey Yota Techers, I have code P0420 on 2007 2.7 Tacoma. I changed both oxygen sensors which were old anyway and still have the code. I tested the catalytic converter with an infrared thermometer and I get around 320 degrees pre cat and around 420 degrees after cat. I made sure to test where there is no heat shield and pretty sure it's accurate readings. Is this normal pre and post temps for our trucks? I live in CA and the 50 state cats are 6 times the price for 49 state. Unbelievable laws!!! I am trying to avoid shelling out $700+. Any input helps. Thanks.

skypilot

iTrader: (1)

Why does that sound way too low??? I know exhaust gases are 1800 degrees at the port, so a working cat should be around 2k degree's. There is a reason for the heat shields, these things start fires.

I know little of CA emissions laws but sounds like your engine is running way too cold, or lean. Check your plugs to see if they are running too hot.

Mike Stabbs

those temps are way low.my ultra gauge showed way more but that was off the O2 sensor too.

75w90mantraN

Those are low, but were the readings taken just after start up or after reaching closed loop / operating temp? Hopefully by now, that's been diagnosed and fixed. Or perhaps move out of Cali to a place that does not require emissions.

I paid roughly over $700 for Magnaflow after dealing with that pesky code.

I forgot alternative methods of checking so a quick search:
https://axleaddict.com/auto-repair/H...ytic-Converter

Mentions the infrared thermometer test.

If you have a scan tool that can read the oxygen sensor (post cat), the way it reads can confirm cat functioning properly or not. A bad one will give a fluctuating or rapidly changing voltage values. Good cat would give a fairly constant reading over time with little change.