P0420 Code Cataylst Below Threshold Dented O2 Sensor

Has anyone gotten a P0420 code after finding their O2 sensor is dented in between the wires and where the wrench goes over it?
I am wondering if this is why I'm having a P0420 code that wont go anyway, its on the downstream O2 sensor on the drivers side pipe.

 

Going to link back to this thread & quote a knowledgeable TW member on the topic that sums it up nicely. TLDR it could be your cats (not the ones that eat Meow Mix).

https://www.tacomaworld.com/threads/hello-everyone.794713/#post-28469593

Good luck with clearing your codes. I'll also add that if you do replace O2 sensors don't get cheap with them. Just from reading around these parts I can recall several threads where aftermarket sensors bite the dust quickly. OEM Denso are by far the best IIRC, you can get them cheaper if you order online versus local stealership.

 

How dented? Pics?

Usually the pcm won't code a 420 until all the o2 monitors have run and passed, but I guess it's possible the sensor could be damaged and still slip past a monitor..

Have you checked for exhaust leaks?

 

I dont have a photo yet. dented enough it could be affecting the wiring in the metal shell though.

If my code reader showed which bank it was coming from and that bank happens to be the O2 sensor thats dented then I may replace it.

 

How many miles on the spark plugs and truck? What size engine?

 

The dent shouldn't really matter. P0420 usually means it's time for a new cat. You could do the temp test to give you an idea if it truly is the cats. I would have someone sit the car at hold the RPMS at 1500 -2000.
The exhaust pipe exiting the cat should always be hotter than the exhausts pipe that enters the cat. This tells you the cat is working properly. If you get around the same temp the cat is bad.

To perform a temperature test, you’ll need any type of thermometer, like an infrared or kitchen thermometer.

• Start your vehicle and allow it to reach optimal operating temperature. Take it for a short drive to let this happen.
• Set your vehicle to park or neutral.
• Measure the temperature at the inlet pipe that connects to the front of the catalytic converter. Repeat for the outlet pipe, which connects to the rear of the converter.
• If the front temperature is the same as the rear temperature, it means that there is an issue with the catalytic converter.

 

!GRE V6 4.0

 

The O2 sensor itself is dented?
May have some damage

 

Well the dented sensor can't have anything to do with the P0420, P0420 is for the bank 1 cat which is the passenger side.

 

So bank 2 code is always the downstream O2 sensor?

 

A V type engine has 2 banks of cylinders, on modern engines they controlled and monitored separately.

Bank 1 is the bank with the number 1 cyl and bank 2 is the opposite side, on the 4.0L bank 1 is passenger side and bank 2 is driver's side.

You say you have a code (P0420) for the bank 1 (passenger side) catalytic converter but the sensor you say is damaged is on bank 2 (driver's side), therefore it can't be related to the converter code.

If it was setting a P0430 or a bank 2 O2 sensor code then that sensor could be a problem.

 

But theres only 2 banks right, bank 1 or bank 2 ?

Bank will be for all drivers side clylinders and bank 2 for all passenger side cylinders??

 

Correct, each bank has 2 catalytic converters (only the upstream converters are monitored), 1 AFR Sensor (upstream) (Bank 1 Sensor 1 & Bank 2 Sensor 1), and 1 O2 Sensor (downstream) (Bank 1 Sensor 2 & Bank 2 Sensor 2).
Each component except the downstream converters is monitored and can generate different codes.

Your code is P0420 which is for the Bank 1 (passenger) upstream converter.

 

All of my CATs have been removed. How is it the upstream convertor? I have spark plug foulers on both downstream )2 sensors.

SOunds like its not the dented downstream one on drivers side but i keep getting P0420 so are you saying that its an AFR O2 sensor ?

I also get P0430 which to me would mean that my spark plug foulers with steel wool are not working.

 

The picture is becoming clearer

 

Well you kinda left those details out earlier...
The defouler trick doesn't typically work well with no converters installed, it works alot of the time to prevent a CEL with a marginal converter but with none they typically don't.
The older the vehicle the less "smart" the converter monitor was.
Older stuff compared upstream vs downstream sensor activity, everything now uses what's called oxygen storage test where it drives the fuel mixture rich or lean and watches the response time of the downstream sensor.

 

Ive got an 07 Prerunner so not sure what level of smartness that would be but i did not realize defoulers would not work well without any convertors especailly with the steel wool trick. I wonder if theres some way to modify wiring to fool computer into thinking the reading from downstream sensors are ok.