On a typical day, you’re driving your vehicle when the check engine light comes on the dashboard for no apparent reason. Concerned, you visit a specialized workshop, and after running a diagnostic scan, the code ERROR P0420 – Low Catalytic Efficiency is displayed. Stay calm; you don’t need to panic and replace your car’s catalytic converter as quickly as possible. It may not be the culprit in this story.
Let’s start from the beginning, shall we? This warning simply means that the exhaust gas filtering system, which operates inside the engine during combustion, is functioning below the expected efficiency level. This can lead to a loss of power and an increase in the release of pollutant residues into the atmosphere.
There are many reasons that could be behind this situation. For a precise diagnosis, problem resolution, and peace of mind for the owner to get back on the road, some important aspects must be considered.
What could be causing ERROR P0420?
Low-quality fuel – burning adulterated fuel can release residues that clog and damage exhaust system components, compromising the efficiency of gas filtering during the process.
Deterioration in ignition components – components like cables, spark plugs, coils, or cylinders may have deteriorated and not be functioning properly, which also affects the exhaust system’s performance, triggering the alert.
Battery voltage – under ideal conditions, this reading should be 12.5V with the engine off and above 13.8V with the engine running. It’s also important to check the engine grounding (the leveling of electrical potential in installations).
Improper canister valve operation – this valve should only open at engine speeds exceeding 3000 rpm to allow the elimination of fuel tank gases. If this opening occurs at idle or if there is any saturation or deterioration, it could be the cause of the problem.
Oxygen sensor failure – the catalytic converter has two sensors capable of measuring at the front and rear, comparing oxygen level fluctuations in the intake and exhaust gases. If the readings remain the same during both phases, it indicates a malfunction in the converter or the sensors themselves.
Timing belt and synchronization with the rotation sensor – a lack of synchronization between these two components can influence the volume of gases circulating in the system, altering sensor measurements and triggering the alert.
If all the above aspects are checked and are functioning well, it’s time to focus on the catalytic converter. Check for any possible cracks that could allow gas leakage before it goes through the entire circuit. Only if this is the case should you consider replacing it.
Tuper is the largest exhaust system manufacturer in Latin America and a market leader. For over 50 years, the company has been producing exhausts, catalytic converters, and tailpipes for all makes and models of cars, both domestic and imported, adhering to strict quality standards. The company keeps up with market evolution, offering a wide range of products in accordance with the specifications of the most demanding national and international standards. To know more.