What is code p0420

User Submitted Video - Three way catalytic converter Bank does not operate properly. The purpose of the catalytic converter is to break down harmful pollutants that are created during the combustion cycle.

By using fine platinum and gold meshes to filter exhaust fumes, the catalytic converter is able to reduce the emissions expelled from the exhaust pipe. The catalytic converter has two oxygen sensors. The function of the catalytic converter is to break down harmful pollutants that are created during the combustion cycle and convert them into harmless gases. You may have an oxygen sensor problem or a catalytic converter problem. Your vehicle has oxygen sensors.

Have your oxygen sensors scoped to see if they are working properly if they are. You have not mention year make or model on vehicle, but these p type code are rather universal. Assuming the codes are active, your most likely cause is the catalytic converter.

Watch this video and learn how to turn off you cars check engine in under minutes with parts available at your local auto parts store. Basically, this means the computer has detected the converter on bank is not storing oxygen like it should. It uses one Osensor in the front of the exhaust, and one Osensor in the rear of the catalytic converter. Description: There is one O(oxygen) sensor in front of the catalytic converter (called upstream), and one behind it (downstream).

When the engine is warmed up and running normally the upstream oxygen sensor reading fluctuates and the downstream one is fairly steady. However, if the downstream Osensor starts sweeping between rich and lean, or constantly reads a rich or lean condition, that’s an indication to the PCM that the cat converter isn’t doing its job of cleaning up the PCM’s mistakes. Oxygen Sensor(s) during the time the computer is activating the Catalytic Converter monitor test.

Changing the oxygen sensors will not make a difference. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. This is not a sensor issue. The downstream Osensor reading should be fairly steady. The most common thing is the.

It is set when the Onboard Diagnostic II or OBD II catalyst monitor can sense a drop in its converter efficiency. The OBD II can monitor catalyst efficiency by comparing the switching activity of the upstream and the downstream oxygen sensors in the exhaust. Normally, these two Osensors will have different readings when the car is running. Replacing the oxygen (O2) sensors may sometimes fix the code , but in most cases the catalytic convert needs to be replaced. Outback with 80miles.

The air pump forces air to the exhaust to lower the emissions. It takes in outside air and pumps it through two one-way check valves into each bank of the exhaust. Most of the time that this code is set, the one-way check valves have worn out or failed and allow water. Catalytic converter replacement: On most cars, unless the engine is running poorly when this code sets, the problem is emission rather than performance related. The code must be addressed before any state emission test, but your car is not in danger of breaking down.

It turns out that most of the issues that set oxygen sensor codes are not a result of a bad sensor. Basically this means that the oxygen sensor downstream of the catalytic converter on bank is detecting that. Background on Oxygen Sensors.

Rather, there could be something else in that system does that’s causing the oxygen sensors to appear faulty. You should see the voltage fluctuate from like. It is first necessary to look at the freeze frame information stored when the trouble code was initially set. L equipped cars and mini-vans. In the majority of the cases, this code points to a bad catalytic converter.

The frontmost Osensor most likely needs to be replaced. Good luck and hope this helps. Replacing your catalytic converter is costly, so, knowing if a new catalytic converter is needed pays off.

Your car’s exhaust system (below) comprises: a catalytic converter (s), at least two oxygen sensors and exhaust pipes. Check engine light came on today. The vehicle has 89K miles on it. Usually when this thing throws a code I come on here and there are a ton of posts on the specific problem and the fix. Catalyst efficiency below threshold bank one is the PO4code your getting.

Annoying as it is, I cleared the code and the light when away. The converter also has the ability to store excess oxygen and release the stored oxygen to promote these reactions. The powertrain control module (PCM) monitors this process using a heated oxygen sensor (HO2S). I followed a Honda bulletin about it and: 1) no exhaust leaks 2) voltage measurements of secondary sensor are normal. It then just says, return car to owner.

By the way, both sensors are Bank 1. Front is Bank Sensor and rear is Bank Sensor 2. L Honda is not cleaning the exhaust of pollution like it should. Cat efficiency codes are generated by the rear sensor. They are easy to change and can be found quite a bit cheaper than $1if you look. Rockauto is a good source.

It is part of the vehicle emissions system. If you are replacing the cat, replace the plugs too. It refers to Catalytic Converter Efficiency Basically, it Engine Control Module (ECU) monitors the chemical constituents of the exhaust, both before and after the catalytic converter.

The Catalyst is really a small furnace that reburns the exhaust and adds more oxygen where necessary,. Fill Your Cart With Color Today!