Hi all:

A few days ago, my '07 GS 350 AWD's "check VSC" message popped up on the dash along with the traction control light, engine light and yellow exclamation mark. I did an engine code scan yesterday and it gave me code P0430 "Catalyst System Efficiency Below Threshold (Bank 2)".

Has anyone else experienced this before? It drives fine otherwise...

 

Yes I have.It means the Catalytic converter for bank 2 is done.It is about a $3000 repair at our Canadian stealerships.I did find a work around by adding a o2 adapter and relocating sensor further out of exhaust stream,that still is working after several months,good luck.

 

$3000?! You've got to be kidding me... hmmm is there any long term negative effects to the car if I leave it as it is for now?

 

It might be possible that the Cat may clog someday,but I ,m sure we will notice that.I did check into the new Cat. which was 1800 - 2200 Canadian.Labour abt 4 hrs.at dealer.My workaround was 20-30 parts,took abt 1 hr. if you can do your self.I can,t remember which side for which bank,but plug for 1 o2 is near floor vent for rear passenger on drivers side ,other is beside front of console on passenger side ,door sill plate clips up carpet peeled back to access,not that hard.Shouldn,t have to remove seats.

 

Try this. Make sure your gas cap clicks to the right a few times. Mine did that the other day. Check engine light came on. It was because of the gas cap lol. In regards to the PO430 CODE do not panic!! 9/10 your cats are good!! They just have exhaust leaks before and after the actual cats. If you want to eliminate the problem for along time buy all your o2 sensors and double gaskets for before and after cats. That'll seal up everything down there and no more escapes will come out. I did that to my 2001 GS430 I had and it went away for good. You have to keep up with the gaskets yearly. I spent the dam near $2500+ on cats. I did it the right way. But when I had inspected the older ones after I did everything they were surprisingly intact still. Those Lexus cats are heavy duty. Just need to be maintained all around them. Like anything else. I hope any of this helps you out. GodBless you and I hope your problem gets resolved!!

 

try downstream o2 spacers, taking the sensor out of direct exhaust..... means ecm thinks cleaner

 

Had the same issue on my 06 GS300 RWD. There is a testing sequence from AllData (attached) that has you check output voltages from your O2 sensors that will indicate which sensor is bad. My OBD II scanner couldn't pull the actual voltages but there was no sulfur smell that some others have experienced when the cat is actually bad. Every shop I spoke to was adamant that it was a bad cat without doing any testing- with quotes coming in at $1800, I wasn't going to "try" a new cat. At this point I decided to start with the downstream O2 sensor which was considerably cheaper. AutoAnything carries the Denso part which is the same as OEM (http://www.autoanything.com/fuel-sys...-oxygen-sensor) so I ordered that and had it installed. So far, the code and warning lights have disappeared.

On a separate issue, the car feels bogged down when trying to accelerate. If you give it enough time, it will get to speed but certainly doesn't have the responsiveness that it is supposed to. Based on other posts, I'm going to try a new MAF and go from there....

 

 

 

Is this an awd? If so you might have a leak on your mid pipes that need to be replaced. If that doesnt solve it, I would do an induction cleaning with full bottle of original seafoam through the intake manifold blanked off top nipple, then remove and clean out the throttle body inside and out. I wouldnt worry about that code, just drive the car more often and likely it will clear on its own. Seems like the car isnt driven much, when cars sit for a long period of time sensors will get tripped.

 

Thank you and yes it's an awd.

 

Remove the cat and soak it in soapy fdis washing detergent overnight and was it down gently. Allow to dry and check whether it clean the honeycomb filter. Cats go for about 600.00 on Amazon. Or you can find a local mechanic who will charge only the labor for it. Good luck!

 

If your mid pipes are leaking exhaust then that cat code does get tripped. Because you own an awd, its best to remove the tin surrounding both mid pipes before they completely rot out your exhaust. Its a design flaw on the awd's, theres fiberglass mating wrap with a tin metal. Over time that collects moisture/dirt/salt etc slowly eats away your exhaust. I would jack up the car crawl underneath with a 10mm unbolt all the bolts and remove it all, most likely the nuts get rusted on and if that the case you can easily cut them off or pry them off. Or have an exhaust shop remove it for you, and inspect if they are leaking.

 

 

If all else fail, your catalytic is shot. Don't waste your money on oxygen sensors. MaybeMleaks or cracks on the catalytic converter.