I have just under 250k on this XF, and since I bought it nearly a year ago have done a major tune up on it consisting of new fuel pump, filter, fuel injectors, coils, plugs, wires, air filters, cam and crank sensors, egr valve, maf, and pcv hoses, and primary O2 sensors. Every sensor replaced is bosch. With the mileage on it and completely unknown service history im pretty sure the cat codes are cat related. The exhaust sound in the cabin is reminiscent of hollowed out cats. And if the car is idling and you open stand behind it, the exhaust smells rich.