# P0420 Racingline Performance



## fqhassan (Oct 29, 2013)

I have a 2005 Maxima SL and received a P0420 error code. I had a shop replace both pre-cats with the Racingline Performance pre-cats. I am still getting the P0420 error code. Any suggestions?


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## smj999smj (Jan 1, 2006)

Some aftermarket converters, even new ones, don't break down the exhaust emissions efficiently enough to pass the ECM's parameters...meaning you'll need to use a different catalytic converter to fix the problem correctly. Another option that "might" work is using O2 sensor spacers on the rear sensors, which partially pull the rear sensor elements out of the exhaust stream enough to make it look like there's an effective change in readings to the ECM that it will pass the efficiency test. 
The other possibility is that it isn't the catalytic converter that is causing the P0420 code. Other possible issues that could cause the code to set include intake air leaks, injectors or fuel injector leaks and spark plugs. To determine this, the diagnostic procedure for P0420 listed in the factory service manual should be performed.


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