Suggestions for P0420 Trouble Code

[BKSIEMEK]

Hi everyone. My 2001 Camry's check engine light recently came on, and I pulled a P0420 code. Is it likely that a CAT would already need replacement? The car only has 60K miles on it. Would you try to change the O2 sensors first and see what happens, or bite the bullet and change out the converter? Any suggestions would be appreciated. I would hate to spend the money for an unnecessary CAT replacement if I can avoid it. Thanks again.

[BMR]

Could be several other, cheaper things. I've never had to deal with this prob, but from what I've read here on TN, it seems to be a difficult one to fix. Here's a link which gives some other possibilities for the cause.

[Mister_Perkins]

p0420

# Inefficient Catalytic Converter(s)
# Defective Front or Rear Oxygen Sensor(s)
# Misfiring engines can also lead to a P0420 code

Common Misdiagnoses

* Rear Oxygen Sensor
* Front Oxygen Sensor

# Most Toyota vehicles need an OEM Catalyst, especially if there is a Catalyst-related software update required. Toyotas usually re-set the P0420 code unless an OEM catalyst is used as a replacement. It is common for mechanics to replace all the Oxygen sensors only to find that the Toyota vehicle required an OEM Catalyst.
# Toyota has extended their catalytic converter coverage beyond the typical Emissions Warranty which is 3years/50,000 miles, which ever occurs first. On many Toyota vehicles the Catalytic Converter warranty has been extended to 8years/80,0000 miles when ever a code P0420 occurs. And on very specific years and models the Catalytic Converter Warranty has been extended even further.

[BKSIEMEK]

Thank you for the info.

[TOYOPARTSMAN]

In order for me to help, I need to know what engine you have, and if you were to PM me your VIN, it may even help further.

Originally Posted by BKSIEMEK

Hi everyone. My 2001 Camry's check engine light recently came on, and I pulled a P0420 code. Is it likely that a CAT would already need replacement? The car only has 60K miles on it. Would you try to change the O2 sensors first and see what happens, or bite the bullet and change out the converter? Any suggestions would be appreciated. I would hate to spend the money for an unnecessary CAT replacement if I can avoid it. Thanks again.

[BKSIEMEK]

The engine is the 2.2L 4cyl

[TOYOPARTSMAN]

PM sent

[Yuko]

My Grandmother's Camry had a P0420 (bad catalytic converter) before. I check the exhaust for leak, bad O2 sensors, talk about reflashing the ECU. But at the end it was a bad catalytic convertor But later I found an easy fix.

I bought a pack of Spark plug Non-fouler/defouler for $4. Drill a 1/2" hole almost though the center to clear the O2 sensor. Screw it onto the post O2 sensor and install it back on the exhaust system. It have pass 4 years of inspections and now at 157,000 mile no CEL.

Here's the package (Sorry I had to borrow a pic from the net)


Here it is installed on the post O2 sensor on the 2AZ-FE, The 5S-FE is farther back on the exhaust.


Here's how it works. The Pre (before) catalytic converter O2 sensor deals with Air/Fuel ratio and measure the exhaust gas. The Post (after) O2 sensor only measure the different of the exhaust gas after the convertor. By moving the sensor a little back from the exhaust gas, it tricks the sensor to think there are less emission. The car still run prefect, Only install it on the post sensor after the catalytic convertor.

Of course the correct repair is to replace the catalytic converter but $954, I'll go for four bucks. On the 2001 Camry with the 4 cylinders, the post O2 sensor is at the middle of the exhaust system. Just install a defouler there and done.

[Solid_Koolaid]

I got this code from my previous 95 Tercel, it was simply caused by an exhaust leak right after the cat, just before the 2nd O2 sensor. Oxygen would get into the exhaust and the O2 sensor would falsely believe the cat wasn't doing its job properly (almost no oxygen should remain if the catalyst is doing its job)

Could be a real mechanical problem though. Damaged catalyst, O2 sensor problem, A/F ratio problems (could be many things), etc.