Does Camry 99 has 2 catalytic converters?
 

I bought 99 Camry. Its catalytic converter, which is in the middle of exhaust pipe, has been replaced with a universal one. So I knew that the car will fail emissions.
Recently it did fail the emission. Codes: P0171, P0420, P0446.

The mechanic told me that catalytic converter is to be replaced. This is what I was expecting. But the part he showed me to be catalytic converter was not in the middle of exhaust pipe. Instead it was next to the engine. This is an expensive part ($700), and mechanic said it is expensive because it comes with exhaust manifold.

Now I am confused. Is he trying to rip me off, by asking me to change the wrong cat? I also want to know if Camry 99 comes with 2 cats?
If there are 2 cats then is there a way to tell which of the two is bad?

Help is really appreciated because the total repair is very expensive (about $1800), and cat replacement alone would cost me about $1100.

Which state are you in? This will make a difference as to what kind of replacement converter can be used.

If you open the hood you should be able to see the first converter, looks like a can attached to the exhaust coming from the head. Yes, the converter is built into the exhaust manifold.

The car was built to either California or Federal emissions standards. If California the car had 2 converters. One is the combo converter/exhaust manifold, the other is under the chassis.

The one under the chassis includes the exhaust pipe that runs to the first converter.

If you are in California you must replace the converters with CARB approved type and these are expensive. If outside California you can use what you want.

However there are alternatives, see link below:

1999 TOYOTA CAMRY Catalytic Converter

If you use these products you may need to find another mechanic who will install it as most shops will only use their products.

As to the codes you listed.

P0446 is for the fuel tank evaporation emissions circuit. Nothing to do with the converters.

P0420 is stating the converter(s) are operating below efficiency. Typically this means a bad converter. However it could be and exhaust system leak or bad 02 or AF sensor.

P0171 states the fuel trim is running lean. Meaning the engine is actually running rich as the computer is trying to compensate for the lean fuel trim. There is a list of reasons that can cause this:

Leak in exhaust system.
Leak in intake air system.
Fuel pressure.
Injector blockage.
02/AF sensor.
MAP sensor.
Engine coolant temp sensor for computer.

As you read. There appears to be a few things in common here. Codes P0171 and P420 can both be caused by bad 02/AF sensor or leak in exhaust system.

Does the exhaust system have a leak?

There is no way to check the converter operation except to run and exhaust emission test before and after the converter. Most shops don't do this.

Typically if the the AF/02 sensors are OK, the exhaust has not leaks, no other codes and the emissions test failure sheet states that N0x is high. One would conclude the converter was bad.

If you are outside California might look at the non-California converters listed at the link. Much cheaper. Again you need to find a shop to install it. The job is easy enough, perhaps you have a friend handy with cars.

I am in Connecticut.

I was pretty sure that the leak was in converter under the chassis. But this mechanic told me that the leak is in converter/manifold combo.

I am not sure what to do at this moment.

The exhaust system does have a leak? If so this can cause the P0171 and P0420 codes.

Use a section of hose as a stethoscope and try to narrow down the exhaust leak.

If you look under the chassis you will see a section of pipe in front of the converter under the chassis that looks like it was made of spun wire.

This is a flexible pipe, allowing the exhaust system to flex as one end is connected to the engine and the other mounted on the frame.

The flex pipe is a common place for leaks.

Listen to this area plus the area around the firs converter and the pipes above it.

Sometimes the pipes above the first converter leak.

You should be able to use cheaper Non-California parts on the car.

If needed, find another shop and get a second opinion.

Suggest you don't provide any details of past work and advice. Just state you think or you can hear exhaust coming from a specific location, the check light is on, can you determine what is wrong.

Compare the answers with the first shop.

You have time to check things out, nothing will be damaged short term. The car will not pass an emissions of course because the check light is on and if the tester hears the exhaust leak this may also be a failing item.

I agree that P0446 is for the fuel tank evaporation emissions circuit. Nothing to do with the converters.