P0420 Cadillac -

Question

I have replaced after market converter,02 sensor, spark plugs still have the problem, dealer says maybe you should have got OEM converter??? Really Can you guarantee that will fix my problem?

Answer 1

P0420 Catalytic below threshold Bank 1

 When it comes to the catalytic convertor , it is not just a emission component, it is a mechanical unit, in order for the catalytic to work it has to go from a lean condition to a rich condition and this is how it control harmful emission. Not only does it have to go from lean to rich to work properly, it is specifically made for a particular vehicle, so this make it as a software unit.

Here is a catalytic convertor that was installed about a month ago. the CK ENG LT came on the DTC was P0420, The vehicles fuel trim and operation of the 02 sensor was working properly, The vehicle was well maintained, the problem was the catalytic convertor. This may just be the case that you have , new just does not mean it works.

Also if the catalytic convertor was recently installed if there is any exhaust leak prior to the catalytic it will dilute the exhaust gas and its efficiency will go below its threshold. and code a P0420