Q: code P0420 on my 2012 Chevy Equinox 2.4L O2 sensors

asked by on November 27, 2017

2012 Chevy Equinox 2.4L My check engine light came on and Auto Zone did my diagnostic test and came back as a P0420 said it was O2 sensor bank 1. I believe my car has 4 sensors, 2 upstream & 2 downstream or 1 center. How do i know which one is bad?

My car has 155380 miles.
My car has an automatic transmission.

The code P0420 for your 2.4 L engine is for the after the catalyst O2 sensor. Your vehicle has only two O2 sensors. One is in manifold before the catalyst and the other is after the catalyst. The code can be from a defective sensor or catalytic convertor. The system should have further tests done to make sure the correct part is replaced before repairs are done since the catalyst is a common fix for this code.

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