my check engine light came on so
I ran an obd2 code puller and came up with this; P0420, catalyst system efficiency below threshold(bank 1)
anyone got an ansewer for me??????
thanks

 

o2 sensor its better to replace both at the same time

 

o2 sensor has been replaced recently(both) but, the manifold sensorwas one I wired myself(new sensor,old connector 4 wire) Could this be cat. converter?

 

i got the same prob. i replaced both on mine and stupid cel still comes on [:@] i just said hell with it even though i still waste more gas but i ll fix it when i go home. have u tried looking at the wires and making sure there not messed up or have corrosion on them. u could also check with the voltage meter or whatever its called to check if the wire is busted.

 

either your cat is bad, or your second O2 sensor is bad