P0420 code and SES/ETS lights

[Reverend]

My GA just threw a P0420 code today, the SES and ETS lights are on steady. Checked OBD and got a P0420 code which is Catalytic converter from what I can find. Could it be something else throwing this code or is my CatCon shot? I have put $500 into this car in the last two months and only driven it 250 miles. O2 sensor last month and starter last week, replaced. I don't have the money to keep up with monthly repairs.
Will this code cause an undriveable condition, where we could get stranded or is it something to deal with when I can get to it?

[black05GT]

As I understand it, that code means that your catalytic convertor is not operating to an expected level - that said, it COULD be the rear sensor, but I would think that you would be getting additional codes.
I've had that same DTC code (because I have a hi-flow cat installed), and driven the car for weeks with no problems with the SES light on - problem is - you don't know it that's the ONLY reason the SES is on , so don't depend on the SES only.
Although I'm not sure why the ETS light is on also, that should be checked into.