What would happen if the wrong catalytic converter was installed in my 2001 Toyota Camry

ANSWER : Hello. The wrong converter will cause your check engine light to come on and will cause you to not pass emissions. It can also cause some performance and efficiency issues over time. There are specific converters built for all vehicles and that is what needs to be used, especially in California. You need to take it back to the shop that installed the wrong one as it is against emission regulations to install the wrong converter in California.

ANSWER : Hi there. Assuming that both engines are the same size, the compatibility of "fitting" should be OK. However, since this is a service we don’t offer, we’re not best suited to provide the best advice on this. I can tell you that a common problem have with replacing motors is communication with the ECU. In most cases, it will require reprogramming by a specialist in order for all the systems to work correctly.

ANSWER : Hi there, thanks for writing in. I am not sure why you changed your catalytic converter. Assuming you had a P0420 code, replacing the catalytic converter should of resolved that code. The codes originally stored need to be cleared. The fact your check engine light remains off tells me, you may have fixed the problem. Try disconnecting the negative battery terminal for at least 2 minutes, reconnect. Start and drive the vehicle for 10-15 miles. Re-check for codes. If a code returns on the first drive cycle (pending code), a problem still exists. The check engine light should come back on (the next drive cycle) if, the fault is recognized by the computer. An exhaust leak before the oxygen sensor will cause O2 sensor and catalytic converter codes. If you are having trouble identifying the fault, consider having an expert automotive technician from YourMechanic come to your home or office to inspect and diagnose this issue for you, and make or suggest any repairs as needed.

ANSWER : Hello. If the exhaust system is original, that is if it is about 20 years old, you will probably end up replacing the entire system, consisting of the "Y" pipe coming off the manifolds, the converter, muffler, and tail pipe. The reason for this is that the catalytic converter mates to the "Y" pipe on one end and to the muffler on the other via flanges with three bolts per flange. These flanges both rust shut and are typically weakened once bent (installed) years ago and thinned out by rust.

You can sometimes attempt to salvage existing parts by using aftermarket flanges and/or split flanges but if the rest of the system is even as little as 5 years old it is not worth it. Also, in your configuration the converter is not set up with straight pipe on either end making retrofit to the existing system less convenient.

If you do replace the whole system, the most critical task is to remove the three nuts on each manifold flange stud without breaking or damaging the thread on the stud. If you haven’t done this before, I recommend that you at least observe the procedure while someone trained completes the job, and then next time around you may have the confidence in taking on this type of job after seeing how it is done. It is a bit of work, and unless you have dealt with exhaust fasteners before, it can be tricky. If you would like a professional handle this, a certified professional from YourMechanic can come to your car’s location to inspect the rattle and replace the catalytic converter for you if necessary.

ANSWER : Hello. Most vehicles do not have to have the catalytic converter replaced unless it becomes damaged due to road debris or it overheating severely. With that said, it is possible your car may be running a bit too rich (too much fuel in the air/fuel mixture), which can cause the catalytic converter to overheat.

When this happens it can become clogged or filter excess gases poorly, which will cause the vehicle to run very poorly as a result (think of a sink being backed up), not allowing it to flush out toxic gases which become backed up inside the vehicle’s exhaust system. If you not experiencing any drivability concerns, I would ask the person why they suggested having it replaced. If you would like to have the car checked for a second opinion, a certified technician from YourMechanic can come to your home or office to give the vehicle a complete inspection.

ANSWER : I think what the mechanic was telling you is that there are two different ways to replace a catalytic converter. The first way is to have factory type parts installed, that will normally come with the converter, and the adjoining pipe sections and flanges with them. Of course, this is typically a more expensive replacement due to the extra pieces and engineering involved. Typically, the less expensive way, is to go to a repair shop that specializes in exhaust work. They will normally cut the existing catalytic converter out and replace it by welding in a universal style converter. There are different schools of thought as to whether the universal style are as good as the factory style, and whether or not they will last as long. A low quality, and some remanufactured, catalytic converters can cause issues due to being less efficient, or will not last as long due to being manufactured with lower quality components. When it comes to converter replacement, I tend to stick with the factory parts as much as I can, as I have had better results with them, over the universal style. If you feel you would like another opinion in diagnosing and fixing the issue, consult a certified mechanic, like those available at YourMechanic.com.

ANSWER : You are right, the traction control system is not related in any way to the exhaust system (e.g., the catalytic converter) in the vehicle. Traction control involves wheel speed sensors, the ABS system, and electronic controllers. If there is a problem with the traction control system on your vehicle, it is likely that diagnostic trouble codes have been stored and those codes will provide the key clues to finding, and repairing, the fault in the system. A certified Mechanic, dispatched by YourMechanic right to your location, can perform a traction control system diagnostic and let you know of the required repairs. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

ANSWER : Hi there. Before you decide to have the catalytic converter replaced in your vehicle, consider performing the following checks:

Check the following:

A damaged or failed oxygen sensor
The oxygen sensor wiring damaged or connected improperly
The engine coolant temperature sensor is not working properly
A leaking exhaust manifold or a leak in the exhaust system
The spark timing is retarded
There is a leaking fuel injector or there is high fuel pressure
The engine has a cylinder misfire
The engine oil is contaminated

If all of the above areas are checked and passes their functions and conditions, then the catalytic converter would need replaced. If you need further assistance with your P0420 code, then seek out a professional, such as one from Your Mechanic, to help you.