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P0420 OBD-II Trouble Code: Catalyst System Efficiency Below Threshold (Bank 1)
P0420 code definition Catalyst System Efficiency Below Threshold (Bank 1) What the P0420 code means The catalytic converter pulls in the pollutants that are expelled by the cylinders and uses oxygen...

Related questions

O2 sensor failed
Hi there. A p0420 usually means the catalytic convert is not performing as well as it needs to. Over time, the catalytic converters fill up with carbon and and will not filter out the exhaust gas as efficiently as they...
Bad O2 sensor
Hello, code P0420 represents right main catalyst deterioration. There can be a few things that need to be checked before replacing parts. The intake system needs to be inspected for vacuum leaks and unmetered air leaks. The exhaust system should...
Can catalytic converter particles damage the engine?
Not really if you think about it. You've got a a catalytic converter which is on the exhaust system. The hot gas comes out of the engine in the manifold and then goes through the exhaust system to the catalytic...
Codes showing: P0171, P0420, P0174
Hello. These diagnostic trouble codes are an indication that there could be a problem with the oxygen sensor or that there is a vacuum leak. It is possible that the vacuum leak is located in the intake manifold. These codes...
Codes P0420 and P0171 appearing
When it relates to the air conditioning system, the dealership does not have an advantage when it comes to hybrid air conditioning systems. These air conditioning systems require special evacuation machines that are different from that of a normal air...
Check engine light code P0420
You may have a purge valve that is leaking and causing excessive fumes to enter the intake manifold during the refuel process. When you start the vehicle, the excessive rich mixture may be causing the catalyst to overheat which will...
Catalyst system efficiency
Hi. There are a few things to check out when receiving this code as it doesn't always mean the catalytic converter is going bad. The car has multiple oxygen sensors that test how efficient the converter is performing. If the...
Diagnosed as code P0420
When you get a P0420 code that indicates a failing catalytic converter. Most of the time that is exactly what it is. In some cases, it can also be caused by a bad oxygen sensor. I typically use a computer...
Can a defective catalytic converter cause clutch failure?
To answer your question, a catalytic converter cannot cause clutch failure. You have a series of independent failures, which is not very common for vehicles with less than 100,000 miles. I would take your 2013 Chevrolet Cruze back to the...
P0420 code after idle relearn
Hello. P0420 is the code for catalyst efficiency below the correct threshold for bank 1. If you do not believe the catalytic converters are the issue, then the first thing I would do is check the bank 1 oxygen sensors....
Engine misfiring 2003 Honda CR-V
Misfires can be caused by several things. I would first check for vacuum leaks, then I would pull the plugs to see if they need replacing. It is possible that have a fuel system concern, but I would lean more...
Code p0420
Hello. P0420 could be due to a variety of faults including even a fuel pump that is not supplying sufficient fuel, causing a lean condition, and hence "fooling" the O2 sensors (pre and post) as to the status (i.e., efficiency)...
Very hard to start vehicle
Hello. This code is also related to the catalytic converter not working properly. This can also happen when the ground wires connected to the O2 sensors are not properly hooked up causing them to send erroneous info to the computer....
I have the P0420 code
Hi there, thanks for writing in. Code P0420 has to do with the catalytic converter in your vehicle. The code will need to be diagnosed by checking the vehicle for exhaust leaks, O2 sensor problems, or the wiring to the...
P0420 code
Honda has a technical service bulletin (TSB) out for this condition. There are 2 possibilities to correct this fault, according to the bulletin: Replace the catalytic converter Software update of the engine computer One last thing...
The car shakes during braking and at stop lights, error code P0420
Hi there. The P0420 code you are getting can cause your car to run like this. The code typically means that the catalytic converter is failing or one of the oxygen sensors may be failing. If it was the...
Reading P2096/P2098/ the past these have came up but are not clearing this time.
The P2096 and P2098 codes are for both of the downstream oxygen sensors. The P0420 code is for the bank one catalytic converter efficiency. It would be best to have a certified mechanic take a look at the vehicle and...
P0420 code and dash lighs on
The vehicle stability control (VSC) light and code P0420 are for two different problems. The VSC system would need to be tested for codes for that system. The code P0420 is for the O2 sensor or problem with...
How to get more horsepower without the check engine light and still still pass smog
Coming from a realistic point of view, I'd say that unless you were to pull your motor and completely rebuild it, from pan to fuel injection, you might want to consider NOT adding components for horsepower. With over 200,000 miles,...
The engine light is on and the code is P0420 - Catalyst System Efficiency Below Threshold Bank . What part do I need to fix it?
While a number of things like a faulty oxygen sensor or exhaust leak can cause fault code P0420 to be set, the most common fault is the catalytic converter itself. However, as a replacement can be very expensive, your best...

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