How many oxygen sensors does the 2012 Volvo XC70 T6 AWD model have on it?
I'm getting a random Bank1 P0420 error code on it.
I figure if one is having the issue somewhere down the line the others will follow.
And, If I'm replacing one, might as well do the rest as preventative maintenance.
the vehicle has almost 270K miles on it now.
Thanks.

Just one cat. A forward O2 sensor usually in the down pipe and a rear sensor behind the cat.

A good life for the front O2 sensor is 100K miles, more than double for the rear. Some have found that installing a spacer for the rear to keep the sensor out of the direct exhaust stream also works well. Don't let the people that inspect cars see the spacer...
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Keeping it running is better than buying new

Hi,

I guess the answer is to know how many catalytic converters does the car have, as the code is saying it not reaching its efficiency temperature.
Bank one maybe the only one it has as I don’t know what kind of engine configuration is used on these cars. I’m a Volvo 240 man.

Yes the sensor could be bad or not enough flow coming through the converter to get it hot!

A substitution of a sensor and a code reset looks to be in order!
I bad signal will cause the engine to not be in optimal tune.
So, if you replace the sensor give it plenty of time to get the converter cleared of any extra contamination
before condemning the converter.
In most cases an engine in good tune doesn’t need the converter.
Of course there are exceptions under extreme loading conditions, like mountain climbing and then, everyone behind you smells the rotten egg smell!

Others that know more will chime in hopefully!

Phil