Questions & Answers for: Saturn SL p0420 code

...P0420 CODE I ASKED THE QUESTION ABOUT MY 1996 SATURN AND YOU JUSST REPLIED ASKING ME A BUNCH OF QUESTIONS... THE CODE IS P0420 YES, THE CHCK ENGINE LIGHT IS ON ok knowing the code is what its all ...

p0420 code shows p0420 codes shows engine light comes on P0420 Catalyst System Efficiency Below Threshold (Bank 1) You have a worn out catalytic converter.

...CODE P0420(UPSTREAM CATALYTIC CONVERTER EFFICIENCY BELOW THRESHOLD) I guess one would come to the conclusion you need to replace the upstream O2 sensor. Buy one at a parts store and take it to a ...

...code p0420 came up Not a big deal...You will need to drain the tank if there is more than 10% the total volume of diesel. If not, fill the tank with 90 to 92 octane and go ahead and run it. It will ...