2000 sable check eng light

2000 sable with the 3.0L EFI DOHC check eng light, the problems started about 6000 miles ago when the catalytic converter went bad. Had to change the converter and muffler. Thats when I started to get code PO420 and then code PO430 I have change 3 O2 sensor so far. The car will run good for 150 miles and the check light come back on. I'am starting to think this car is about to be a money pit and I don't have the money SOMEONE PLEASE POINT ME TO THE LIGHT.:banghead:

P0420 Catalyst System Efficiency Below Threshold Bank 1
P0430 Catalyst System Efficiency Below Threshold Bank 2
O2 sensor replacement will not help.
The catalytic converters are covered under the emissions warranty, even if you are out of the regular 36/36000 warranty.

P0420 Catalyst System Efficiency Below Threshold Bank 1
P0430 Catalyst System Efficiency Below Threshold Bank 2
O2 sensor replacement will not help.
The catalytic converters are covered under the emissions warranty, even if you are out of the regular 36/36000 warranty.


The car has over 100.000 miles on it I drive about 25.000 miles a year. Can you till me the origin of the problem, warranty is no longer good and, I changed the main catalytic converter already and the o2 sensors so what else could it be :banghead:

This is just by logic, not actual experience. But, for the computer to know that the catalytic converter(s) are bad, there must be a sensor PAST the catalytic converter in the exhaust flow. If the converters are good, then the sensors must be bad. Also, around where I live, every catalytic converter replacement business gives a one-to-two years warranty. Yours should have some kind too, and the OBD clearly indicates (to their satisfaction) that those converters are not working (assuming that the post converter sensors are OK) There is a lot of fraud and fakes in the car parts business, the higher the item cost, the more likely of the abuse. Catalytic converters are pricey items, I'm sure it's not exempt from faking in the Far East (China specificalliy, and in particular)

This is just by logic, not actual experience. But, for the computer to know that the catalytic converter(s) are bad, there must be a sensor PAST the catalytic converter in the exhaust flow. If the converters are good, then the sensors must be bad. Also, around where I live, every catalytic converter replacement business gives a one-to-two years warranty. Yours should have some kind too, and the OBD clearly indicates (to their satisfaction) that those converters are not working (assuming that the post converter sensors are OK) There is a lot of fraud and fakes in the car parts business, the higher the item cost, the more likely of the abuse. Catalytic converters are pricey items, I'm sure it's not exempt from faking in the Far East (China specificalliy, and in particular)
Thanks I guess I'll have to go to the dealer because there is a pre-Catalytic converter before the o2 sensors and that is a dealer part and it is very costly, :banghead: but at least I tried about eveything before taking it there.

[QUOTE=aldavsable00]Thanks I guess I'll have to go to the dealer because there is a pre-Catalytic converter before the o2 sensors and that is a dealer part and it is very costly, :banghead: but at least I tried about eveything before taking it there.[/QUOTEi had aproblem like that with a 97 sable there is a sensor that controls your egr flow called a differintial pressure feedback sensor (dpfe) and the diagnostics said it was a bad o2 sensor. you can not get this part at autozone or advance it's a dealership part and costs around 80 dollars