How urgent is a Rear Oxygen Sensor Replacement?
The rear oxygen sensor is less of a troublemaker than the front oxygen sensor. For the most part, the rear oxygen sensor just polices the catalytic converter. So, it’s unlikely to leave you stranded and it shouldn’t cause any additional harm to your vehicle.
But it will keep that annoying check engine light illuminated and, really, do you want to look at that thing every day? Plus, a bad rear oxygen sensor can cause you to fail a state emissions test – and nobody wants that.