Phosphorus is the main concern today for fouling a converter. Phosphorus is found in motor oil. So is zinc, which can also cause trouble. Normally these trace metals do not cause a problem. Once this happens, there is no fix other than to replace the converter. Trouble is, the new converter will eventually suffer the same fate as the old one unless the cause of the oil burning is also repaired -- which typically means overhauling or replacing the engine.
Sulfur is another contaminant. It is found in small amounts in gasoline. As long as the concentration is limited, it causes no problem. But too much sulfur in a batch of bad gasoline can create a rotten egg odor in the exhaust and cause the converter to light off at a higher than normal temperature, increasing pollution and possibly damaging the converter. Silicone is an ingredient in traditional antifreeze. Silicone is used to provide corrosion protection for aluminum parts. As long as it stays inside the cooling system, it has no effect on the converter.
But if the head gasket starts to seep coolant into the combustion chamber, or the head develops a hairline crack that leaks coolant, silicone can get into the exhaust and ruin the converter. As with phosphorus contamination, it is essential to eliminate the source of the coolant leak before the converter is replaced, otherwise the new converter will suffer the same fate.
You should also note that silicone, phosphorus and lead can also contaminate oxygen sensors, too. If the converter has failed because of contamination, the oxygen sensors should also be checked because they may be contaminated, too. The converter can handle quite a bit of heat.
However, high levels of pollutants coming out of the engine cause the converter's operating temperature to soar. This can damage the converter. If the converter overheats over degrees F , it can actually melt the ceramic honeycomb inside the shell.
The result may be a partial or complete blockage that causes a sharp increase in exhaust backpressure and a big drop in engine performance and fuel economy. If the converter is completely plugged, it will cause the engine to stall. Underlying causes here include things like fouled spark plugs, bad plug wires, leaky engine valves or a leaky head gasket. The only way to know if emissions are really a problem or not is to give the vehicle an emissions test. That's why states test vehicles every couple of years to check emissions compliance.
A converter that works well enough to keep emissions within limits at idle may literally run out of air at higher speeds allowing too much pollution to exit the tailpipe.
To work efficiently, a converter needs to capture and hold oxygen when the mixture is lean so it can burn the pollutants when the mixture is rich. A special "washcoat" of aluminum oxide on the honeycomb increases its surface area by a factor of almost 7, times, allowing it to trap and hold the extra oxygen. But if the washcoat has been damaged or contaminated, the converter may not be able to trap enough oxygen causing a drop in efficiency.
It's supposed to run on every "trip, which is a drive cycle that begins with a cold start and continues until the engine reaches normal operating temperature. But the monitor monitor won't run until all the "enabling criteria" are met.
As a rule, the vehicle will have to be driven at highway cruising speeds for at least 15 minutes to get the catalyst monitor to run. The catalyst monitor will not run if the OBD II system has detected a conflict with other tests such as the EGR, fuel system or purge tests , or there are hard codes or pending codes for a misfire condition or oxygen sensor.
If the test runs and the OBD II system detects too much of a drop off in converter efficiency, it will set a pending code. If the same condition is noted on a second or third trip, the code will mature and turn on the MIL lamp. If you plug a scan tool or code reader into the vehicle and discover a generic OBD II code P to P, you've diagnosed a converter problem. Now the question becomes, is the converter really bad?
That's a question that isn't so easily answered. The only way to know for sure is to give it an emissions test. But here's the catch. Even if it passes a tailpipe test, it may not be emissions legal as long as the MIL lamp remains lit. The only way to extinguish the MIL lamp may be to replace the converter. Remember, the OBD II system is calibrated to detect potential emissions problems that may cause emissions to exceed federal limits by 1. It would be the side that has two cylinders on it that would be called bank two.
Both the front and rear sensors of a catalytic converter are responsible for monitoring oxygen levels. Its only function is to monitor the amounts of oxygen in the catalytic converter throughout the combustion process. Whenever the catalytic converter fails to function properly, hazardous emissions from the car escape into the environment. A faulty catalytic converter might also have a negative impact on other components of the automobile.
Code P is related to:. Code P might emerge during a diagnostic check due to a variety of issues, making it difficult to diagnose and resolve. The most frequently seen issue is a malfunctioning or failed catalytic converter. Among the other reasons are:. You should address any issue that is causing your check engine light to illuminate as soon as feasible, since these issues may have catastrophic repercussions if left unattended.
Code P is mostly responsible for drivability problems. However, while these concerns are not life-threatening, they might present difficulties on the highway, particularly if you find yourself unable to accelerate. If you do not address the issue as soon as possible, it might result in substantial and costly damage to other car components.
The catalytic converter is often responsible for the appearance of the P code when this component of your vehicle is either malfunctioning or defective. Making a little investment in an exhaust system cleaning is a fantastic starting point. However, even the most effective catalytic converter cleaning has its limits. Continue to run the cleaner through the exhaust system and check to see if the P code reappears after clearing the check engine light with an automotive diagnostic tool not included.
Make certain that you obtain your repair from a company that is well-known for doing thorough diagnostic examinations. While your catalytic converter problem continues to exist, other codes, in addition to the P code, may appear. You should deal with such issues at the same time as you deal with the P error number. Insight about a more substantial, system-wide problem may be gained from their observations. It is possible that codes other than the P code will appear while your catalytic converter problem is being investigated.
These problems should be addressed at the same time that the P error code is resolved. Insight into a more substantial, system-wide problem may be gained via their investigation. Replacement of your oxygen sensors is a logical first step in this situation, particularly if you are also receiving a signal that indicates a probable electrical issue with them. There are four pieces of information you must be aware of in order to get the best catalytic converter on the internet: 1.
Confoundingly, there are converters available for automobiles that were originally fitted with CARB emissions but are no longer CARB-legal, as well as converters available for vehicles that have switched sites over their lifetime. On the few occasions where there are physical size discrepancies between the California and non-California halves of the state, this is the case. Using an item that has the executive order E.
For any parts professional, distinguishing between reality and fiction may be a difficult endeavor. This is not necessarily true. More information is available by clicking here. However, some people feel that when a P or P diagnostic issue code is logged, the catalytic converter must be changed immediately.
These are challenges that any parts expert may have to deal with on a daily basis, especially in areas where severe emissions inspection rules are in place. Manufacturers of automobiles fitted oxygen sensors at the intake upstream and exit downstream of the catalytic converter in order to do this. Because of the heat generated by the catalytic converter, the downstream oxygen sensor at the bottom transitions from providing a switching signal to providing a constant voltage signal.
As long as the catalytic converter is capable of breaking down HC, CO, and NOx into their constituent parts, the downstream oxygen sensor will report a steady voltage. When a catalytic converter fails, the signal from the rear oxygen sensor begins to duplicate the signal from the front oxygen sensor, indicating that the converter is no longer functioning properly. If the vehicle has an in-line engine with one catalytic converter, the PCM will record a P diagnostic trouble code DTC indicating that the converter efficiency is less than the Federal Transportation Administration FTA specifications.
Is it possible to avert a P or P catalytic converter problem code by replacing one or both oxygen sensors? It is necessary to update or recalibrate the original diagnostic criteria embedded into the PCM in order for it to function properly under real-world operating situations when a catalytic converter or an oxygen sensor fails for no apparent reason. All technical service bulletins TSBs published by the vehicle manufacturer relevant to catalyst failures must also be checked to determine whether any revisions to the reprogramming or calibration procedures are necessary.
However, when everyone involved depends on facts rather than falsehoods, selling replacement catalytic converters may be considerably less of a nuisance than it otherwise would be.
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This P obd2 code indicates that there is a problem with the catalytic converter, oxygen sensors or both. When this code is stored by the ECU, the malfunction indicator lamp will come on. This is your first sign that there is a problem somewhere in the emission system. Can a bad O2 sensor cause P? How do I know if I have a bad O2 sensor or catalytic converter? Can a bad O2 sensor throw a cat code? Should you replace O2 sensors when you replace catalytic converter?
How do you diagnose a bad catalytic converter? Diagnosing Catalytic Converter Issues step 1: obtain vehicle history. Step 3: Correct Exhaust System Leaks. Step 4: Check Converter Temperature. Step 5: check backpressure. What is a dummy oxygen sensor? How can a slow responding O2 sensor affect the catalytic converter? Can a vacuum leak cause a P code?
How long can you drive with a bad oxygen sensor? How do I fix error code P? What repairs can fix the P code? Replace muffler or repair leaks in the muffler. Replace exhaust manifold or repair leaks in the exhaust manifold. Replace exhaust pipe or repair exhaust pipe leaks. Replace catalytic converter most common Replace engine coolant temperature sensor. Some systems, Subaru of the late 's for example, are unable to maintain mixture control at or near stoiciometric when the pre-catalyst sensor becomes disabled.
Others have no problem maintaining fuel control on both banks even when only one rear sensor is operative Lexus LS Fuel control strategies have changed over the years. In the 's and early 's system designs tended toward simple direct feedback logic. The mixture sensor sends its signal, the controller adjusts the mixture via changes to the injector on time, combustion happens, and then the sensor reads the new adjusted mixture, and so the feedback cycle continues.
This system works but is crude by current standards as it is mediocre when it comes to optimal fuel mileage management and very poor at the fine level of mixture control need by the catalyst for optimal emission control.
This is the system design commonly known and quoted among technicians and amateur internet forums. It is where the myth that the rear mixture sensor only tests the catalyst comes from. Newer designs have changed significantly. This logic type has been labeled "feed forward". It uses Neural Network learning logic and memorized previous engine response parameters to achieve fuel control that gets a clean tailpipe and better power. This method uses an air fuel ratio sensors pre-cat and standard O2 sensor post cat.
The AFR sensors test for misfire detection, mixture variation among cylinders and exhaust temperature. The rear sensor checks average mixture, catalyst output temp, and for a few seconds when conditions are right monitors catalyst heath.
Direct feedback is not used as it is much to slow to keep the mixture in the range needed. Fuel control logic varies greatly over the years and between manufacturers.
Blanket statements about how it is done are unlikely to be supportable. However, one can discern some of how it is done on any given vehicle by watching graphed mixture sensor data on an extended test drive. Two-sensor lambda control combines the beneficial aspects of both upstream and downstream sensors.
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