Q: P0420 P0430 trouble codes

asked by on

I recently changed out the o2 sensors in my car do go an oil leak that also got into the exhaust but I didn't drive it for more than a few miles due to the fact it was smoking so I fixed the leak and changed the o2 sensors and if fixed that problem but not the P0420 and P0430 codes are coming up do u think it could be the sensors I used (universal ones) or maybe I did some thing wrong or is it because of the oil got into the exhaust and clogged the catalytic converters

My car has 150000 miles.
My car has an automatic transmission.

Hello. Thanks for writing in. The universal oxygen sensors, a bad connection, or a bad catalytic converter can all be the cause of the codes. If you can you access to a known good oxygen sensor and test it in the vehicle, then you can rule out that as an option. Universal oxygen sensors are fairly new to the market and may have faults. You will also want to check the connection to the sensors to make sure they are clean, dry, and tight. If the oxygen sensors have been proven to be ok, then you are likely looking at a bad catalytic converter. You should test the oxygen sensors and the connections first before resorting to inspecting the catalytic converter.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. P0420 P0430 trouble codes

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Q: Does it have struts or shocks?

Hi there. The 2006 Cadillac CTS has a front shock / strut assembly as opposed to the singular strut with coil over spring option that is common with passenger cars and some smaller SUV's. I would recommend having this service...

Q: Engine overheated, liquid sprayed all over engine and other places.

Unfortunately, it would be difficult to say what exactly happened. From your description, the most likely case is a radiator or heater hose was loose or damaged. Cooling system hoses should not be wrapped with any kind of tape under...

Q: Do I need to change the exhaust manifold when changing the Catalytic converter? Your quote is 500 cheaper without it. Do I really

Hello, thank you for writing in. Typically the catalytic converter does not require that you replace the exhaust manifold. The exhaust manifold refers to the manifold of tubes that connect from each piston, and bring the exhaust together to the...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.