See5

Hi guys,
Many 2IS owners faced the same problem:
The following comes on at random times and goes after few days:
-Check VSC
-Traction light is on
-Check engine light is on with trouble code P0430 for bank 2 or P0420 for bank 1.

Possible Causes:
- The catalytic converter is no longer functioning properly.
- An oxygen sensor is not reading (functioning) properly within the same bank side.
- There is an exhaust leak.

Solution:
I would start to trace any problems from the bottom of the possible causes list.
My IS350 has 110k miles and I had this problem for just about one year now.
In my case I had p0430 code which means bank 2 ( Driver side ).
So I started by going to a local welder because I was already smelling intense exhaust smell coming into the cabin when cold starting the car.
The cause was very clear, a wide exhaust leak in the pipe right after the cat.

Fix:
Oxyfuel Gas welding was used to weld the leakage. The welder asked me to start the car and rev it after he finish to check if the weld is still present. I did this four times maybe, until he eventually ended up with perfectly tight and smooth weld.

Here is the weld :







Cost: $14

Comment: I wonder why Lexus use these rusty pipes instead of stainless steel pipes

Bichon

On the 2IS, a P0420 or P0430 DTC is usually caused by precisely the kind of rust damage that you and your welder found.

Your fix is certainly cost-effective, but I'll curious to see how long it lasts.

srt1

You shouda changed out that nasty pipe cause that rust will, in time, eat at that pipe.

See5

When it occurs again I will probably make a custom straight 2.5" stainless steel pipes, at a cost of $800 !.

But yeah, I assume this fix would last for a couple of years or so. The shop does this kind of welding all the time, it is certainly not a permanent fix though. Looking at the bright side you get what you paid for

See5

If I replaced the pipe instead :
A new OEM would come with the resonator,
Part # 1741031J00
Price $1,415.52 !!


I would never recommend buying a new oem pipe, just make a new stainless steel custom made for you for half the price and double the quality .