N63T: Oxygen Sensor Internal Resistance Faults. The Service Engine Soon light comes on with either or both of the following faults stored in the DME memory: ? 12B701 - Oxygen sensor heating after catalytic converter, function: Internal resistance too high ? 12B801 - Oxygen sensor heating after catalytic converter 2, function: Internal resistance too high The engine operation and performance are not affected. The DME diagnosis for the post catalyst oxygen sensor(s) is too sensitive.
