Code P0420 Catalyst System Efficiency Below Threshold (Bank 1) Diagnosis
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getitright (08-20-23)
02-05-12, 03:39 PM
#17
No, you misunderstood me. I had 2 exhaust shop's check for leaks and they could not find any. What I was saying is I did not switch the 02 sensors to see if it would be a bank 2 code nor did I run the Seafoam through the intake. All 5 dealers I spoke with said it is the cats. 02 sensors would set a specific code and not a generic code.
Last edited by Lavrishevo; 02-05-12 at 03:49 PM.
02-16-12, 12:27 PM
#19
Update:
500 miles later and no more CEL. I took the chance that it was drivers side cat and not the 02 sensor. I was told by multiple dealers that 02 sensors set their own specific codes and not generic ones but I am not sure if this info is specific for later model LS400's or specific to the pre-cat 02 sensors. One thing I do notice with new Magnaflow cats though is that the mufflers are a bit louder when driving with the windows down.
500 miles later and no more CEL. I took the chance that it was drivers side cat and not the 02 sensor. I was told by multiple dealers that 02 sensors set their own specific codes and not generic ones but I am not sure if this info is specific for later model LS400's or specific to the pre-cat 02 sensors. One thing I do notice with new Magnaflow cats though is that the mufflers are a bit louder when driving with the windows down.
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