I have a 2000 Tacoma V6 . Has the Po420 code . I’m hesitant about replacing the cat Do to a mix up when I look at the live data of the O2 sensor and the Fuel air sensor. . The scan tool is giving me a reading of 3.3 volts on O2S1bank2 I’m reading as the second sensor and 1 volt on O2S1bank 1 . I do have the correct sensors in the correct place . The OEM fuel ratio befor the cat and the O2 after the cat . Is it possible they could be hooked up on the computer side or a fuse box . Also where would I look to swap the connection
I was a little confused by the wording of your question but I think I understand what you're asking and correct me if I'm wrong.
You're wondering if the wiring of your upstream O2 sensor (in your case an AFR sensor) may have been swapped with the wiring of your downstream O2 sensor, (somewhere in the harness), and you're receiving "reversed voltages" on your scanner.
The easiest way to see if that's happening is to go to Live Data on your scanner, unplug the downstream O2 sensor, and see if the voltage for the upstream AFR sensor disappears on your scanner
Yes you are in the same page I will check the down stream O2 and see what comes up with voltage
I just rechecked and I was wrong both sensors are hooked up correct. I guess it is probably a bad cat . I have replaced both sensors charcoal canister (had a crack ) Maf , air filter, battery is good , gas cap , purge sensor, cleaned ICV , new hoses . Can’t find any leaks . The peaks on the Air Fuel sensor seem lower than the O2 after it warms up . Very confused. I’m going to try a Caticlean and see what happens . I did take the converters off and no cracks and no sign of carbon . I soaked them in detergent soap over nite . Replaced with OEM gaskets . This is a California IM truck .