P0430 - Catalyst System Efficiency Below Threshold (Bank 2)
We don't get involved with costs here because there's way too many variables. First of all, diagnostic fault codes never say to replace parts or that they're defective, but in this case it is referring to the catalytic converter and nothing else. Your mechanic must first do some electrical tests on the rear oxygen sensor to verify it is working properly. If it is, most likely the catalytic converter needs to be replaced. We don't know its cost, the amount of time needed to replace it, or your shop's hourly labor rate. Replacement converters may be available from different sources too at different costs.
The first problem with ignoring the problem has to do with the Check Engine light itself. It is there to tell you when the Engine Computer has detected a problem. How will you know if a second, totally different, potentially serious problem occurs? The light will already be on and you'll still be ignoring it. Some problems are relatively minor but will turn into very expensive ones if they're ignored.
The second problem is the Engine Computer is constantly running a lot of self tests and is watching numerous operating conditions. To set a diagnostic fault code when a problem is detected, there is always a long list of conditions that must be met. One of those conditions is that certain other codes can not already be set. The computer looks at multiple sensor readings and reconciles them to each other. Some sensors can set a code on their own, AND when a good reading doesn't correspond to the reading from a different sensor. If what is used for comparison has already set a code, the computer knows it can't rely on that so it will not run some other tests and / or it will not set some codes when there is nothing trustworthy to compare to.
In this case the second problem can cause running problems and customer complaints, but with no related fault code, the mechanic is left with just the first, original code that has nothing to do with the current problem. He will waste a lot of time and your money trying to figure out why the code that IS in memory is related to the running problem you're having.
The second problem is that when you DO have the cause of the first code diagnosed, and the mechanic gives you an estimate, once the repair is done, the computer will resume all of the other tests. THAT'S when the second fault code will finally be set and the Check Engine light will turn on again. You blame the mechanic for not diagnosing the problem correctly when in reality he did a proper repair for the first problem and had no way of knowing there was a second problem. This type of thing happens most often when you ignore the first problem for weeks or months. That gives the second problem more time to develop. Mechanics hate having new problems show up while they're working on your car and they hate having to tell you more parts or services are needed, but they have no way of knowing that until they diagnose and repair the initial problems as they show up.
Thursday, September 19th, 2013 AT 12:49 PM