DTC Code P0421 Catalytic Converter Problem?

Question

I'm getting code P0421 it says Warp Up Catalyst Below Threshold (Bank 1.) Here are the problems with the car, no power (rpm takes too long to get up there,) when I accelerate and then slow down the car vibrates (misfiring?,) and theres this buzzing sound when the car is on idle. Can these all be related to the same problem? What should I do 1st..buy a new cat, fuel injector cleaning, or change spark plugs? also i'm realy busy at school, would i be creating more problem if I am in fact driving around with a bad cat?

Answer 1

It sounds like the catalytic converter. By law their warranty is at least 80000 miles. If your car has less than that take it to the dealer and they will replace it at not cost.

Answer 2

The cat is a very serious problem if not attended to...basically your cat's internals are melted together and is blocking the exhaust gas from escaping...not good. it will hurt the engine.
the loss of power, and the buzzing sounds can be attributed to the problem. But remember, the cat went out for a reason. Most likely a rich fuel mixture. Check your plugs, wires, cap, rotor to make sure they are firing well. Next, check your O2 sensor reading. If there is no malfunction, then it is probably just your cat. Fuel injector cleaner is for the most part a big scam. You don't need it unless your car is really misfiring like its going to die. But at 5.00 a bottle, it is a cheap try, see what happens!

Answer 3

Catalytic convertor is plugged. This will cause low power, vibrations and a possible odor. This can also cause internal damage to the engine if not corrected soon. You want to replace the o2 sensor(s) as well.

Answer 4

looks like the cat is clog.( the buzzing sound)

if the car give up then ......You know what You have to change ....don't even look for the problem You know it.

but wait until gives up

Answer 5

The federally mandated warranty on the converter is 7yr/90,000 miles. If you have less than that on the car, the dealer will change it for free.

Answer 6

Impossible to say without knowing the year and make of vehicle.

Answer 7

first off, call the dealer to ask them what exactly that means. itsyour best bet, and the mechanics would most likely be happy to answer.

Answer 8

buy a new cat.sounds like the cat is bad.