420 code cat code runs good,can it be cleaned up

Po 420 cathalytic ineficient i say on you tube a guy you clean is cathalytic convertor with seafoam i try to find it for you

Ok your 301,302 thats a misfire cylinder 1and cylinder 2 spark plug coil pack you should get away with that but the 420 that a cathalytic code me i would change the spark plug first try it after if its not missing that problem is good me i would clear the code and try it like that if it doesnt come back good for if not the convertor is a problem im gonna add a video on how to clean that cathalytic try it before changing it p.s if you got a 301 302 your car engine most shake 2 cylinder missing if it doesnt shake or miss try clearing the code first you dont no maybe work was done on it and the code werth clear the video is exactly the same code as your but its a bit extreme you could by seafoam and run it in the trottle body directly its gonna smoke but its gonna clean it

you will get this code when the incompletely burned fuel in the cat has built up to a certain level and cat can no longer absorb more. The cause of incompletely burned fuel in the cat can be due to many reasons:

1. sparkplugs not firing correctly (wrong gap or fouled)(problem with ingntion components(wiring to spark plugs to high resistance)
2. fuel injectors are fouled.
3. bad fuel, incorrect fuel (regular vs premium-see user manual)

You will have to verify plugs are good, plug wires are good, injectors are clean, fuel is good.

once you get these things line out the light will eventually go out.

What was the code given..
02 will mostly sensors..
Cat code 420 will need new cat
And evap codes can b a couple different parts..need exact codes to tell what all is needed for fix

code p0420 refers to cat converter system, bank 1 efficiency below threshold===causes --cat converter--wiring HO2S sensor 2

check that the cat converter is ok and replace the sensor. ( it is a HO2S sensor which will be different to a O2 sensor so get the right one )

420 form hell.
are you required by law to fix thaT. SURELY I'D NEVER KNOW.
What it means i lazy CAT
or engine is running real bad. or both.
that is what it means.
420 is the CAT monitor DTC test.
and will fail if..
engine runs bad.
front 02 is bad.
rear o2 is bad, in that order.
if all that order? is IN ORDER>
the the cat is NO GOOD..

02 means the OXYGEN SENORS, 02 name in physics,
oxygen like to pair up atomically (due to valence)

p0420

no FSM> and not looking up P0420?
no engine stated, so ill get it wrong too..?????????????
420 is cat monitor failure. "efficiency"
the most hard of all.

ill make a list from hard and expensive .
1: bad sensor 2 rear. you failed to do both, that was WRONG.
2: bad cat. (i can weld on any cat for $99 bucks.) i do it last.. dead last.
3: engine running real bad. BUY a scan tool, now.

so the o2 is new that leaves #2 or #3.
i never shot gun cats. but shops do, its not their cash, huh?

i connect a real scan tool (not one that misses factory DTC codes)
then look at pendings for P042o , see funny sensor readings there, bingo.
i check every PID. for all sensors to be sure they READ right.
ECT AT 180F+ AND HOLDING? HOT.>?,
is the engine holding closed loop status at idle, no fix that NOW.
is LTFT (long term fuel trim ) near 0 or at - 40 or + 40% (fix that next)
if trim is good, the engine.
If the front 02 is new, the AFR will be correct and the the front 02 will swing fast and the trim will be near 0 , -4 is near best.
tad rich , natural.
once the engine is running Stoich at light flat cruise. (close loop) the
cat will heal its self (bake dry) and stop throwing 420. ( a hope deal)
if not the cat is bad.

ive cured some of the most hard 420s,.

on some ratty engines, a new cat can in fact hide it , until it cooks to death and next year 420 are back.
id never do that because gas is expensive. fix engine first.

420 is a catalytic converter afficiency code. It could cause by many problems: bed fuel, old spark plugs, sensor wiring connection. I would replace plugs and fill with premium fuel, turn off the code and drive to see if it comes back. If it does, stop by any muffler shop and have them run cleaner threw your system, it may give you 5 to 6 month driving but sooner or later you will need new cat for your car. Hope it helps.

Neither have anything to do with each other. The cam sensor is used to fire the injectors. The O2 sensors is for fuel mileage and to monitor the catalytic converter. If the O2 sensor is bad it will throw O2 codes and maybe a cat code (420). If the cat is bad, then only P0420. If the cam is bad it will set a cam code, but the ECM will go in default mode and still run the engine. Bad gas mileage, yes, But will still run. Best way to check a cat is remove the O2 sensor closest to the engine or loosen the exhaust flange. If it runs better, the cat is clogged up. Have the codes checked..

P420 is EGR system malfunction P1406 is EGR pintle position problem be sure and check power and ground before condemning the valve and the P401 is catalyst code i would fix EGR code first clear monitors and run a drive cycle to see if the cat code returned although the egr and catalyst are separate systems an EGR that isn't functioning may cause the emissions levels to be too high for a marginal converter to diffuse resulting in the cat efficiency code