[BoxsterSenior]

My 01 Boxster ‘S’ Tip (69,000 miles) has started to throw P0430 codes about every 200 miles this winter. I have read from previous postings that “generally” the P0430 indicates the Bank 2 pre-cat is not functioning properly, as determined by the front and rear O2 sensors. My question is it the pre-cat or the O2 sensors, or something else?
With my Durametric reader I collected the following readings after a 10 mile normal drive.
At idle and 180 degrees engine temp……….
BANK 1
Front O2 sensor voltage readings: 0.08 to 0.78 fluctuating (like roller coaster)
resistance reading: 128 steady (flat line)
Rear O2 sensor voltage readings: 0.68 to 0.76 steady (flat line)
resistance reading: 320 steady (flat line)
BANK 2

Front O2 sensor voltage readings: 0.09 to 0.78 fluctuating (like roller coaster)
resistance reading: 64 steady (flat line)
Rear O2 sensor voltage readings: 0.65 to 0.79 steady (flat line)
resistance reading: 192 steady (flat line)

All (4) O2 sensors heater voltage: 2.05 v

Observation: The front and rear O2 voltage readings for both Bank 1 and Bank 2 are almost identical and acting the same. However, the Bank 2 resistance values are approx. 1/2 of the Bank 1 values.
Could this be cause of the P0430 error code…….the O2 sensors rather than the pre-cat???
[no P0420 (Bank 1) codes observed]

ADDITIONAL Durametric reader information…
Ready Status….
Cat Conv Effectiveness …………………………Pass
Fuel Tank Ventilation ……………………………Fail (no explanation)
Secondary Air System …………………………Pass
Oxygen sensors …………………………………Pass
Oxygen sensor heaters …………………………Pass

Would the fuel tank ventilation (fail) have any effect on the P0430 code?
Fuel cap about 2 years old….seal looks good?

Also, MAF cleaned 200 mile ago.
Any and all suggests will be welcomed.

Thanks, Phil