P0420 Chevrolet Code - Catalyst System Low Efficiency Bank 1

The vehicle is hesitating in first gear. Therefore, it is quite sluggish going up hills or taking corners. Have changed downstream 02 sensor, spark plugs, and throttle body assembly.

What model and year is your Chrysler? The P0420 code shouldn't cause a problem with the engine performance, unless the Catalytic Converter is clogged and causing poor engine exhaust flow.

2009 chevrolet Traverse, just replaced spark plug and coil on #1 cylinder, then code came on after driving the next day

i have code p0420 can i fix this my self and will it hut car if i drive like this

hurt the car if i drive it

2006 CHEVY COBALT

You probably have to replace the catalytic converter. It won't hurt your vehicle if you keep driving it like that, but it won't pass the smog test.

99tahoe , just had transmission rebuilt, now has a po420 bank 1.
I noticed at 70mph and in overdrive truck feels sluggish and I need to manually drop it into drive in order for it to accelerate without any kind of hesitation if I don't manually change gear , it feels like truck has a dead spot in throttle and it doesn't kick down with any authority and sorta "lugs " does having the transmission rebuilt and the code related ? And the apparent sluggishness at higher speeds?

No, the transmission repair is not related to the catalytic converter problem. The sluggish problem could be caused by a partially clogged catalytic converter.

If there are no exhaust or intake leaks, you may have to repalce the catalytic converter. Before you replace the cat, try changing the air filter (part of the maintenance anyways) and use high octane gas for a couple weeks.

Copy. Would you be able to hear the exhaust leaks or just visible inspection. Plus I just replaced the air filter with the K&N factory an hour ago and use mid grade in CA. I haven't had a chance to get it on the road yet.

Depends on how bad the exhaust leak is, but usually, you can hear the noise.

Ok because I haven't heard and can't hear a thing!

Could you use sea foam or multi system tune up to see if smoke would come out of other places other than the mufflers? maybe if leeks are present at the cats you can see smoke from there. or also the intake or manifolds ? putting it through the vacuum line?

Yes, sea foam could work.

catalyst efficiency below threshold bank 1 =p0420 and p0420pd model 2009 Chevrolet tahoe.. please What's the mean this? And what I have but to solve this problem?

What I have buy ** to solve this eror..

You have to replace the Catalytic Converter

2003 Chevy Suburban gave me this code with a check engine light on. Is there an easy fix?

Try using high octane gas for a couple of weeks.

I HAVE A 2013 CHEVY SONIC...i got codes p0420?

The P0402 code means that the catalytic convert is not working properly. More than likely you have to replace the catalytic converter to fix the problem. You could try using high octane gas for a couple of weeks, sometimes that will take care of the problem.

2012 GMC 2500HD 6.6 Duramax got a P0420 error code

The problem is more than likely the Catalytic Converter.

2001 chevy impala ls 3.8 ltr engine 120.000 miles have code p0420 and have had cat. converter replaced 2017 and 2 weeks ago had both O2 sensors replaced as well (Bosch branded) and fully seated also PCV also replaced 2 weeks ago... error code and intermittent/hard cold start.

Other than the catalytic converter, the things I have seen triggering the P0420 code on the 2001 Chevy Impala are Coolant Temperature Sensor (Which could also cause a hard start), fuel pressure regulator, ignition coils, intake plenum gasket.

Did you use a factory Catalytic Converter? some aftermarket catalytic converter fail prematurely.

I changed my air filter in my '09 Traverse and managed to lose 2 of assembly torx screws, my P0420 code came on about 8 days later ... any chance that caused the code?

It's somewhat possible. Have you tried to clear the code?

I have a p0420 code, had the cat replaced and the code is coming back up and reading as permanent. Any ideas....

What model and year is your vehicle? how long it takes for the code to come back? did you use a OEM Catalytic Converter? How long ago did you replaced the catalytic converter? I apologize for all the questions, just need to get more information to help you.

2014 chevy sonic lt. Was noy an oem cat. Order from walker cat as am exact fit. Just put the cat on yesterday. Code came back on in about 15 miles. I dont know if it was ever clear correctly in the first place.

Never had that problem before,even aftermarket cats fix the code for a little while. Make sure there are no exhaust leaks, if no leaks are present, then try clearing the code and reset all systems by disconnecting the car battery for about 1 hr.

I replaced the oe sensors catalytic converter spark plugs can someone help me also I replaced the gas cap 26 dollars for the gas cap.it comes on on the dash I don't know what else to do.it could be something with the fuel .I don't smell any fuel leak tjou.

Do you have any other codes beside the P0420 code? any other symptoms?

My Cadillac cts 2004 p0420 and p2190 is on my checking engine light is on what is it my email address is [email protected]

I have a 2011 Chevy equinox ltz 4cyl. It’s saying catalytic converter low emission I was told to replace cap. Can you help

Replace the gas cap? No. The code is for the Catalytic Converter and you must replace the Catalytic Converter to fix the problem.

I have a 2013 Chevy equinox last year I replace the catalytic converter it worked at whole year now it came back P0 420 bank one I replace exhaust manifold I replace air intake gaskets the O2 sensors I put them on new a year ago The light is still on check engine light I took it to another shop they said it was a misfire but I keep up with my cars maintenance I change the plugs oil change every time it needs it the only thing I see with my car did it jerks at a stoplight or when I started in the morning in my garage it starts to putter don’t understand it I was reading on some reviews and a lot of the Chevy equinox do that

Did you use a factory Catalytic Converter? some aftermarket cats won't last too long.

Also, there is factory service bulletin for a Premature Catalytic Converter Failures.

https://static.nhtsa.gov/od...

I have a 2014 Chevy Sonic. Pulled code P0420. Replaced the converter w/ an non-factory part and the code came right back. Is there a procedure that needs to be performed for the computer to see the new cat, or do I need to go factory?

Did you clear the code with a scanner? You must clear the code and drive your vehicle. Then, if no problem is found by PCM, the code will not again.
If you replaced the catalytic converter and cleared the code, but the code comes back, then there is something else setting the code, which is unusual.
Do you have any other symptoms?

i have a 1999 chevy suburan and P0420 catalyst system efficiency below treshold bank 1 and code P0174 system to leam bank 2... but it doesnt show engine light on

I have a 2007 Chevy Avalanche and the P0420 /p0430 came Up.

I replaced all 4 Sensore first and cleard the Code, but a day later the same Codes came back again.

So i repalyced the Catalyst with a Factory new one. cleard the code and a day later after a drive the Codes came Back again.

Any Suggestions ?

I readed that it possible could be a Gasket from the Intake or maybe a cracked Intake maybe one injector, but for that the engine runs to smoothly in my opinion. What could possible wrong ?

I found a Factory Service Bulletin with the following information:

A SES light may be experienced on low mileage vehicles, or vehicles that have recently had the catalytic converter replaced

Upon inspection, DTCs P0420 and/or P0430 may be stored.

If the DTCs set shortly after the catalytic converter is replaced, it may be a result of the engine run time restrictions no longer being in place since the vehicle is no longer new. As a result, the catalytic converter may not have completed a thorough break-in cycle after replacement, possibly resulting in a false DTC P0420 and/or P0430. If this occurs, clear the DTCs and perform the drive cycle below.

In order to achieve proper catalytic converter temperature and allow the mat material to out-gas (break-in), perform the following drive cycle and suggestions:

1. Drive vehicle at sustained highway speed for 25 to 30 minutes
2. Bring vehicle to a stop
3. Shut off the engine for 1 minute
4. Restart the engine and resume highway speed for an additional 10 to 15 minutes
5. Bring vehicle to a stop
6. Shut off engine for 1 minute
7. Restart the engine and operate vehicle at the conditions for running the DTC P0420/430 tests and assure that the vehicle passes these diagnostic tests.

If the engine light is not ON, then try clearing the codes first. If the light comes back, you must try to repair the P0174 code first.

Common causes for the P0174 codes are:

- Intake air leaks
- Faulty front heated oxygen sensor
- Ignition misfiring
- Faulty fuel injectors
- Exhaust gas leaks Incorrect fuel pressure
- Lack of fuel
- Faulty Mass Air Flow (MAF) sensor
- Incorrect Positive Crankcase Ventilation (PCV) hose connection

P0174 CHEVROLET - Fuel Trim System Lean Bank 2
Read more: https://www.autocodes.com/p...

i have a 2018 tahoe has a po420 code had it for a couple months has 155,642 miles on it what can i do to repair it.