Before I run out and spend $250.00 on a new catalytic, I wanted to confirm that the code 0402 requires the replacement of the front exhaust "y" pipe which attaches to the exhaust manifold and has the welded inline CAT. I have a 1999 V6.

I have read thread's regarding O2 sensor and sensitivity with the aftermarket converter. There does appear to be a second unit under the car on the horizontal plane of the exhaust system. I believe the faulty unit is the more expensive unit which is part of a "Y" pipe and is more forward on the exhaust system close to the exhaust manifold.

Can anyone confirm???

 

Welcome to the Club.

You mean P0420.

That is related to the main catalytic converter underneath the vehicle.

I have had no issues with my aftermarket converters in this spot and I don't even have the front precats anymore. Similar 1MZFE fed-spec Toyota Solaras have a similar setup.

Have you been getting this code repeatedly?

 

I have had that same code and it turns out i had a pin hole leak right in front of my o2 sensor in front of the cat.

 

Just goes to show you how sensitive OBD II really is.