How do I fix this code p0420 - 2001 Dodge Grand Caravan

Your catalytic converter is probably shot. You should climb under your car with a small ball peen hammer, a very light one and gently tap your mufflers and the catalytic converter. Many have a cover over them to avoid brush fires from tall grass... they get very hot. It you hear any internal rattling around, replace the muffler or catalytic converter. If they sound and rust-free, it could simpy be a bad catalytic converter sensor. Replace your Oxygen sensors on the exhaust system too while you at it to make your car more fuel efficient... DENSO and BOSCH make them for most cars, with DENSO's being a bit better. Unless your car stalls or gets poor mileage or your State has emissions testing, it not unsafe to drive the car as it is.

You should get all you need to know here:

OBDII Code P0420 DODGE Catalyst System Efficiency Bank 1 HelpForCars net

You need to have it check out by a qualified repair shop because you don't want to guess on this one ! This has to do with the catalytic converter , if it's work or not ! The car needs to be hook up a up scale scan tool to check it out . Catalytic converters can cost as much as a Thousand dollars , so you want to be sure ! How To Diagnose Check Engine Light Code P0420 Catalyst Bank 1