Hi, people.

I have CEL and Trac OFF lights on my RX330 (2004) . it shows P0420 code.

I heard about CataClean fluid, any opinions about this fluid?

And check this video also http://www.youtube.com/watch?v=5icTmYItwiE


So what do you think?

 

Better off changing the sensor. I've used lots of additives (and some that others regard as snake oil I've found success with), and I looked into fluids to clean the cat area given my issues in Mexico with their gasoline and the high altitude. The problem with fluids that would affect this area is that they have to not only pass through the combustion cycle but also get through one or more sets of pre-cats before even reaching the cat. I've researched a lot of these fluids, but haven't found one that could really fix such an issue.

The P0420 code is usually someting that can pop up temporarily. I often saw these codes pop up for people in Mexico when going uphill in hot weather, code was reset and nothing else occurred. However, when this code keeps popping up over and over, the usual culprit is the O2 sensor after the main cat underneath the vehicle if the P0420 is your only code your showing. Sometimes it liked to pop up with P0171 or an A/F sensor code, that's not your case here.

It's a rare case that it winds up being the catalytic converter itself, especially running U.S. gasoline.

Someone with a more advanced OBD2 scanner maybe able to get the readings and freezeframe information for the P0420 and see that the sensor reading is.

 

Than you for your response and time you spent writing it!
I have my own scaner ELM327 and it show P0420, P0420*, P0430*.

PS. How can i check O2 sensor by myself?

 

The only other way is through an electrical tester and you'd have to get to the electrical connection that runs underneath the carpet (behind the driver's seat, at least with the RX300 (can't remember the RX300) offhand and measure through the top of the electrical connection (if I had a manual offhand with me I could check this). I know the value offhand with the RX300 is 11-16.

The only other thing that comes to mind here is the possibility of a small leak somewhere along the exhaust piping, but I've had those myself over the years on my RX300 and never a single P0420.

 

Unfortunately, simply seeing if the O2 sensor is responding or not is not enough to tell us if the code is set because of the cat or the O2 sensor...

There are 4 wires to the O2 sensors on modern cars *typically*. Two wires are for the heater circuit, one for ground, and one for the sensor voltage signal. We need to find this voltage output and look at it. It should register between 0.1 and .95 volts. It is easier with an old school analog volt meter, as it should sweep back and forth between rich (.95) and lean (.1) If it is stuck one way or the other and consistently stays at either end, then the O2 sensor is not working properly. If it sweeps back and forth, then it may be working properly. Why the word "may" - simply because the ECU looks at the primary sensor as well and compares the sensor voltages... You may be able (should, perhaps?) to see voltages using your ELM scantool... Also, if you do need to check voltages manually, it is probably easier at the ECU harness instead of the O2 sensor itself...

As far as making a catalytic converter work better, or clean it, well, I'm not sure soap and water will help, and running that stuff through your engine - well, the fuel lines weren't designed for it and it could easily cause damage to them...

Did you ever try the reset procedure I posted in the other thread?

We should also look at primary O2 voltages and see if they are sweeping as well.

 

Also, Lexmex - you may not see it often, but I get at least 1-2 cars per month that come in for diagnostic and the issue is a catalytic converter failing...

 

Interesting to note. In Mexico, it was a common sight and I had my own issues with my cats down there, but later on the gasoline got better (sulfur ppm and quality in general) and still have my last cat that I go put on down there. Gasoline was typically better in areas like Mexico City (anywhere with higher pollution) as opposed to the rural areas. Mexican vehicles didn't get cats until about 1991.

If only there was a real magical elixir in a bottle.

 

Good info, fellas!

I cleaned CEL couple times and it is still coming ON with TRAC OFF.

Today i connected my RX to ELM and i have no idea what this numbers mean.
With cold engine:

O2 Sensor 1, Bank 1 0.740 V
O2 Sensor 2, Bank 2 0.760 V

O2 Sensor 1, Bank 1 (WR) 7.995 V Eq ratio: 0.999 (ranged from 3.222 to 7.995)
O2 Sensor 2, Bank 2 (WR) 3.222 V Eq ratio 0.993 (ranged from 3.222 to 7.995)

 

Your bank 1 sensor 1, voltage should vary between .1 - .9. If it's shows 0.740V then you got a bad oxygen sensor bank 1 sensor 1. Not sure if your car has A/F ratio sensor than thats a different story

 

You need a new catalyst converter. The P0420 is for "Catalyst system below threshold". Your car has the Air Fuel sensor or A/F sensor as a pre-cat and O2 sensor after the cat. Your A/F should read around .325-.335 volts and your O2 (Bank1/2 sensor 2) should read some where from .1-.9 volts but the O2 only monitor oxygen after the cat and it will stay at the same reading for a while before its change.
The 04 RX had a recall on the cat,but that was a limited recall for the cat. came apart and rattle inside the exhaust.Your car is no longer cover under that recall.

 

I had the same code the p0420 at first they said it was an o2 sensor, I changed it the light came back on they changed it again, it stood off for almost 2 weeks, so i took it to another mechanic he said its the cat. it might just be clogged. go buy a cat cleaner that comes in a green can. I bought it been driving the car for 2 weeks so far and no light. also changed my air filter

 

It'll be back most likely... If it was clogged you should notice a loss in power...

 

If you think the cat is clogged, do a back pressure test. It's very simple with a vacuum gauge. You can google it.

 

MAF sensor -OK
O2 sensors - OK
Rear CAT - Dead

Already replaced it.