I was driving normally and all the light came on last week on thursday. I had disconnected the battery and the lights went away, but it came back on today again wednesday. I guess I will have to get the codes pulled. From what i have researched, it is most likely the o2 sensor or gas cap. I am looking up prices for o2 sensors. Is bank 1 sensor 1 upstream left or right? I am going to replace the o2 sensors with denso. My car just hit 110k miles.

 

Hope it's the gas cap like mines! My seal was wore out.

 

downstream o2's will not trigger 'check vsc', only CEL.
upstreams will tho.
DO NOT just 'replace the o2s'. Get the car scanned first.
It may be anything from VSV for ACIS to bad VVTi oil control valve.

 

How can you tell the seal is worn out? I will take a look at it later tonight.

 

I will get it scanned. Im going to remain optimistic and hope it is just the o2 sensors or gas cap. The ones you listed sound expensive to repair. Thanks

 

Nnnnope =) both malfunctions i described are kinda 'usual' for LS430 and both are in range of 100-200 bucks repair.
I had almost every 'weak spot' malfunctions happen to my LS: both downstream o2's (had to cut out the cats), vvti oil control valve (100usd, can be replaced DIY in about 15mins). haven't had any of the upstreams go tho. upstreams are still original. but it's dependent on quality of gas i suppose.

EDIT: vsv for acis happens on almost every ls430 at some point. the vsv ('vacuum solenoid valve') is like 80 bucks, but replacement is kinda hard-ish, cos of necessity to remove the intake manifold. but as i remember correctly, the vsv for acis error gets displayed on the screen as 'VSV FOR ACIS MALF'...

 

Well I got the code read and it comes up with p0420 something about bank 1. Is that the o2 sensor?

 

Yeah, Post cat O2 sensor. Emissions sensor. Bank 1 is drivers side. 2 - passenger. One of three things. Exhaust leak, even very minor, bad sensor, or bad catalytic converter. The sensors can be tested with someone who has a code reader that can monitor real time values of the post and pre cat sensors. You can look how they react in parallel when running the engine and minor revs. It's a comparison of values and how closely they match. A good mechanic should be able to do this. This way you can tell if it is a lazy 02 sensor or your cats. If it is your cats you should do both at the same time. I would not pay for oem personally. Get CA complaint cats if you go aftermarket. Magnaflow is who I like.

Another option. Disable both post cat 02 sensors.

 

That ^^^^^^^^

 

How do I disable post cat sensors? If anything, I can just do a cat delete.

 

You cannot disable them. You can use the spacers tho! Spacers work.

 

Can you elaborate on what spacers you are talking about? I keep thinking of wheel spacers lol.

 

There are a few companies out there that make 02 simulators that will work on the 430. Don't remember the names though. Going to have to search.


Edit:

Found it - http://www.magnumtuning.com/en/detai...us/ls-430/4-3l

 

Oh ok. So basically trying to replace the post o2 sensors is pointless? I find it hard to believe the cats would go bad already only at 110k miles. I always use premium fuel and regularly change out my filters and clean the maf once in a while

 

I would start with the presumption that your cats are fine. Probably a bad O2 sensor or exhaust leak.