Help needed diagnosing CEL fault codes

[PKN]

Gentlemen

My 2006 Cayenne TT is throwing codes and engine fault light is on. The codes from my Durametric are as follows;

P0150 - O2 Sensor Bank 2 Sensor 1 upper limit value exceeded

P2146

Neither faults are currently causing the CEL and it might take a few days after cancelling the fault before they show up again. My engine had done over 90,000 miles and I am suspecting the 02 sensors are coming due for replacement.

My local autoparts store had one Denso 02 sensor compatible with my car for pre-cat so I bought it. I don't want to fit it though unless one of the old pre-cat sensors is bad. They did not carry a Bosch in stock and it is a lot more expensive than the Denso which cost me $110 for one (234-5117). As always, the invaluable help of the experts on this board can hopefully point me in the right direction before I spend several more hundred dollars to replace all 4 sensors

PKN

[Loren]

P0150 Oxygen sensor in front of catalytic converter, bank 2 – signal implausible

Possible cause of fault- Leaking bolts on the oxygen sensor- Leaks in exhaust system between engine and catalytic converter- Oxygen sensor in front of catalytic converter faulty (shift in characteristics/pollution)

P2146 Power Supply of fuel injectors

Possible cause of fault- Short circuit to B+ / ground or open circuit in the line

- Fuel injector faulty

[PKN]

Loren

Many thanks for the rapid response. I will check the fuel injector connections and switch out the 02 sensor before the cat on the passenger side of the car. Can you advise if I need to get at the sensor from under the car or can it be done through the wheel arch liner. Too damned hot to go near it right now....

PKN

[Loren]

V8 only...

4 and 14 are pre-cat O2 sensors - bank 1 and bank 2 respectively

6 and 12 are after cat sensors - bank 1 and bank 2 respectively

[PKN]

Thanks again Loren. It would help if I was looking at the correct side. Still not sure of the best way to get to it - from underneath?

PKN