niik

Hello everyone,

I just bought a beautiful 2006 LX 470 with 200K miles, and I have a few things to put right before I can fully enjoy it.


The other day I got a P0430 code, which turned on the CEL and disabled VSC
The code means Catalytic Converter Bank 2 Below efficiency, OK I got that.

I tried to use Torque Pro with a bluetooth OBD2 connector, and displayed all the O2 sensors that were available:

02 sensor 1 Equivalence Ratio (1.00V)
02 sensor 1 wide-range Voltage (3.27V)
02 sensor 5 Equivalence Ratio (1.00V)
02 sensor 5 wide-range Voltage (3.24V)
02 Volts bank 1 sensor 2 (0.68V)
02 volts bank 2 sensor 2 (0.76V)

The last one (bottom right on the picture) seems to be all over the place.
All the others move more or less together, except this one which peaks and drops more dramatically.
As you can see even at idle, it moves when the others appear flat.


Also, Torque tells me that the value should be between 0.039 V and 9.xx V and that the current value is 0.03 V and that the fault P0430 is pending.

I want to fix what needs to be fixed, but I would like to rule out a defective 02 sensor before I replace the cat if necessary.
In fact, I would expect both cats to be shot if there was an engine problem before, not just one.

Could anybody knowledgeable help me by telling me how to proceed by elimination to find the true source of the problem.

When I bought the car, the fuel cap was not clicking properly, and the car threw in a few codes regarding this. I replaced it with the correct original one from Lexus.

Thanks in advance.

Nik

niik

To answer my own question, I found that Torque was a PITA to work with.
I got a USB MINI VCI cable, but I am still struggling somehow to get it recognised. Oh well.

I cleaned the throttle body. The MAF sensor was very clean, so I decided not to touch it.
I put some spark plug defoulers to move the O2 sensors a bit further from the exhaust. The numbers somehow improved (like from 0.03 V to 0.19 V) but definitely not enough for my problem.
I changed the O2 sensor on the faulty bank (I thought I might as well do this if I have to change the cat anyway), and the number climbed a little bit more (to say 0.24 V). Still not enough.
The other bank does not throw a code with a value of 0.5 V (which I assume is also too low but not quite enough).

So, the next option is to change the cat, right? When I gently knock it, there is no rattling noise or anything.