I have a 1996 Toyota Camry and my front catalytic conveter is not working properly. The one that has an 02 sensor and connects to the manifold in front of the engine. Does anyone know a cheap place I can get one? I live in California, it must be california approval, because we are require to get smong check here.

all v engines have 2 or 4
i can be different for calif. cars.. are yah?
1996 is USA (calif , federal versions)
1998 is canada
3.8L: V6
the version that has a crossover ,bank 1 to bank 2.
so shares a cat ,and has 1 sensors in front of cat on manifold
and 1 for the cat. rear.
the rear 02 is seen a wire to a grommet under drivers seat
to the cat rear. 02 sensor
the front sensor, is under wiper motor, the book says it must be removed, wiper motor. first


just for you, a photo of rear exh man.
marked up

o2 marked
Cr for cross over to front bank (a pipe)
T for tail , it goes to the CAT.





2 sensors here, !

They all do, they are bathed with flames from engine combustion many times a second. They often glow a nice cherry red. The heat keeps the o2 sensors and catalytic converter clean.

YOU HAVE 2 OXYGEN SENSOR UPSTREAM OXYGEN LOCATED ON THE EXHAUST MANIFOLD. THE DOWN STREAM OXYGEN SENSOR LOCATED BEHIND THE CATALYTIC CONVERTER.YOU CAR HAS ONLY 2 OXYGEN SENSORS.

v-6 has two O2 sensors, one located in the exhaust manifold and the other near the catalytic converter

The secondary oxygen sensor is typically located behind the catalytic converter somewhere on the exhaust. You will need to get under the vehicle to look for it. it should have wires coming out of it leading up to the engine bay. It should be fairly easy to replace. It screws in just like a spark plug

A code P0420 may mean that one or more of the following has happened:

• Leaded fuel was used where unleaded was called for
• An oxygen sensor is not reading (functioning) properly
• The engine coolant temperature sensor is not working properly
• Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe
• Retarded spark timing
• The oxygen sensors in front and behind the converter are reporting too similar of readings

Some suggested steps for troubleshooting a P0420 code include:

• Check for exhaust leaks at the manifold, pipes, catalytic converter. Repair as required.
• Use a scope to diagnose the oxygen sensor operation (Tip: The oxygen sensor in front of the catalytic converter normally has a fluctuating waveform. The waveform of the sensor behind the converter should be more steady).
• Inspect the downstream heated oxygen sensor (HO2), replace if necessary
• Replace the catalytic converter

There are 2 sensors. The main one is located in the exhaust manifold (facing you as you look at the engine from the front of the car). The secondary sensor is located behind the catalytic convertor, which is under the car, approximately beneath the front passenger seat. On some cars, somewhere around 1999, Toyota started using an air/fuel sensor instead of an oxygen sensor in at least one of these locations, so you need to be sure which one you have before replacing. They are not interchangeable.

Not just a faulty catalytic converter will trigger this code. Many other issues can trigger this code.

• Leaded fuel was used where unleaded was called for
• An oxygen sensor is not reading (functioning) properly
• The engine coolant temperature sensor is not working properly
• Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe
• Delayed spark timing
• The oxygen sensors in front and behind the converter are reporting too similar of readings

Possible solutions:

• Check for exhaust leaks at the manifold, pipes, catalytic converter.
• Replace Coolant Temperature Sensor
  
• Use a scope to diagnose the oxygen sensor operation (Tip: The oxygen sensor in front of the catalytic converter normally has a fluctuating waveform. The waveform of the sensor behind the converter should be more steady).
• Inspect the downstream heated oxygen sensor (HO2)
• Replace the catalytic converter
• Have timing adjusted
  

It could all be related.P1537/38 are the intake manifold runner controls are stuck open.They are controlled by vacuum solenoids.The P0171 is bank one of the engine is running lean,usually caused by a vacuum leak, P0420 is catalytic converter efficiency code. The computer monitors the switch rate of the front 02 sensors and compares it to the switch rate of the rear 02 sensors to tell if catalytic converter is doing its job. Now if the front 02 is not switching properly then this will cause this test to fail and set this code.
Look on bottom section of the intake manifold at the back of engine(where tranny bolts up) you should see the vacuum motors there on the intake,these are the control motors for the intake manifold runners.Make sure the vacuum lines are hooked up and lines are not leaking. Also you will see a lever from it to intake make sure they move and are not binding.

Well, if you have the 6 cylinder, there are 3 02 sensors in that car.
One on front manifold, one on back manifold, and one in the center pipe.You changed one, good idea to change the other 2. That is if you have the 6 cyl.