![]() ![]() ![]() So, automatically screwing in a new sensor because there’s a sensor-related code is a big gamble. It turns out that most of the issues that set oxygen sensor codes are not a result of a bad sensor. Now That You Have Some Background, Get to a MechanicĪ trouble code that points to an oxygen sensor (such as p0420, p0135, p0141, or others) is only the first step in your mechanic’s diagnosis of the problem. These are the common things there are plenty of other, often obscure reasons why an O2 sensor codes might be set. For this reason, we highly recommend a diagnosis prior to performing any replacements. This is a costly repair, but common with a p0420 code. If that leak is upstream of the sensor, it will see the extra oxygen and set a trouble code. But air can also be sucked into the pipe at the same leak. Any confusion will throw a code and that pesky CHECK ENGINE light as well.Ī leaky exhaust pipe obviously can let exhaust gases out of the pipe at the leak. The computer can become confused about the readings. Similarly, a partially plugged fuel injector (there’s one for every cylinder in your engine) might inject too little fuel into a single cylinder. The danger is that the extra fuel injected to compensate eventually winds up being burned in the catalytic converter. This makes the computer think it’s not injecting enough fuel. Because the oxygen in that cylinder isn’t burned up, the extra oxygen in that cylinder winds up passing over the O2 sensor. Wires that are broken, melted against the hot exhaust pipes, or corroded, will give erratic or missing readings.Īny of these can cause one or more cylinders to misfire. Sensors have four fragile wires leading up to them, two for the signal to the computer, and two for a small heating element that helps them get up to their operating temperature more rapidly on a cold startup. It’s wise to check further and see if there’s something wrong that made it fail. As you’ll see, it’s a bad idea to simply replace a sensor. Occasionally, a sensor can fail outright, often by being poisoned by leaded gasoline (not very common nowadays), or atmospheric chemicals. When the computer is slewing the air-fuel ratio up and down multiple times per second and the sensor can’t keep up, there’s a code set, illuminating your check engine light. Sensors can and do fail, usually just by getting lazier and lazier until the computer doesn’t trust their output anymore. ![]() Common Causes of a p0420 Code (or Something Similar) This is actually the case with most check engine codes. Rather, there could be something else in that system does that’s causing the oxygen sensors to appear faulty. Oxygen sensors are only a part of a greater system, meaning if the p0420 code (or p0141, or p0135) is thrown, that doesn’t necessarily indicate the oxygen sensors need replacement. This sensor checks the performance of the catalytic converter, making sure it scrubs the last vestiges of pollution from your exhaust. A second sensor is screwed into the exhaust pipe right past the catalytic converter. This sensor allows the engine computer to constantly adjust the amount of fuel sent to your engine, assuring proper combustion and the best performance and emissions. There’s one sensor right ahead of the catalytic converter. Your car will have at least two sensors, and as many as four (unless it’s more than 20 years or so old, in which case it may have only one or none at all). The engine’s fuel injection computer uses oxygen sensors to constantly fine-tune the amount of fuel injected into your engine. ![]() p0420 Code: Time to Replace an Oxygen Sensor? Background on Oxygen Sensors Commonly, people think the p0420 code indicates that the oxygen sensors need to be replaced, but that’s definitely not always the case. It’s actually a generic code, meaning it can be thrown from any vehicle after 1996. When check engine lights are scanned, a p0420 code is a very common result. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |