P0420 Toyota -

Question

PO420 bank 1 code.2006 tacoma 4.0L automatic. Which sensor is bank 1 ahead of the cat or behind it on passenger side?

Answer 1

Hi there,

Bank 1 is the driver side of the engine. If it's a bad sensor then it would be the O2 sensor AFTER the converter on that side of the engine. Most often the issue is the converter however and not the sensor.