Question: I have a 2001 Jeep Grand Cherokee with the 4.0-liter six-cylinder and about 120,000 miles. I keep getting a catalytic converter code P0420. I heard there may be a way to fix it by ...

P0420 is the generic code that was likely stored in your vehicles computer to indicate that the catalytic converter efficiency is below the manufacturer's specified threshold.

P0420 code represents “Catalyst System Efficiency Below Threshold, Bank 1.” It is usually, but not always, caused by a bad converter that’s not reducing emissions output as it should.