Catalytic converter issue

[Whitese7en]

Getting a PO420 code on my 2003 Camry. I've been told that it is a catalytic converter code, however I've also been alerted to a TSB on the Camry 02 Sensor which trips a faulty code for the catalytic converter. I've been told that this is really a computer problem and that it needs to be updated. Apparently once the computer is updated it will stop showing the faulty code.

Are any of you aware of this TSB?

[somick]

I am not aware of any TSB but what I know is that P0420 code means "Catalytic converter 95% below threshold" Some people fool the computer by installing a five dollar ring instead of buying a new exhaust and paying Toyota to reprogram ECU.

There is a lot of threads of this kind here.

Sam

[Brian R.]

Here is the TSB to which you refer (from somick's post at ToyotaNation ):

TSB 02404

“Some 2002 - 2004 model year Camry vehicles equipped with the 4 cylinder (2AZ-FE) engine may exhibit a M.l.L. ON" condition with Diagnostic Trouble Code (DTC) P0420 (Catalyst System Efficiency Below Threshold, Bank 1) in the Engine Control Module (ECM) (SAE term: Powertrain Control Module/PCM). The ECM (PCM) logic has been modified and a redesigned catalyst has been provided.
NOTE :The repair procedure in this TSB is similar to TSB No. EG013-04 "Excessive Sulfur Dioxide Odor." The recalibration of the ECM (PCM) should only be performed ONCE.”

===========================

If the above ECM problem is not the cause, it is probably the HO2 sensor after the catalytic converter not responding normally.

1. Check for leaks in the exhaust system between the engine and the cat converter (loose connection, rusted area, or burned out seal)

2. HO2 sensor after cat converter is bad (measure resistance as above - should be 11-16 ohms cold). <= Most Likely

3. HO2 or A/F ratio sensor before cat converter is bad (remove connector and measure resistance between terminals +B and HT - should be 0.8-1.4 ohms cold).

4. Cat converter is bad.

If you need to replace a sensor, bring your VIN to a Toyota dealer and get the correct part number for your engine. There is only one that works correctly, but at least two available. You don't have to buy the part from Toyota, but you have to have the correct part number.