Hi everyone, I’ve searched the forums (as well as what seems like the entire internet) for an answer but could not find a definitive one. Long story short: bought an LS430 dirt cheap as a project. UL, everything working on the inside (massages, heated/cooled seats, mini fridge, even steering column adjustments both ways). Mechanically- no such luck with. Most of the issues was sorted out by certified mechanics, there are two issues that I’m trying to get rid of still. One, looks like, is a returning one and the other seems new. Before taking care of it the timing was wrong to the point of only one head working (passenger side). The VVT sensor on the drivers side was literally chewed into pieces by one of the camshafts and the misalignment made the sprocket on the shaft carve out some of the aluminium in the engine head. New sensor was put in, timing rebuilt, head smoothed out. New oil pump and some pulleys as well.

After finally being able to drive it for a while one thing started popping back - VSC off light accompanied by P0340. So I’ve bought and replaced 1930050020 but again, no luck with getting rid of the code. Sometimes it stays for days, sometimes only until I turn the engine off and on again. I’ve checked the wiring as far as I could follow it, looks good and definitely not being interfered by the timing belt. What’s more, I’ve recently stumbled onto this thread and seems the sensor I’ve checked might not be the one that needs checking: https://www.clublexus.com/forums/ls-3rd-gen-2001-2006/793626-camshaft-position-sensor-error-refuses-to-go-away-2.html
VVT sensor on the drivers side was the one in pieces and was replaced with an OEM one, however a used one I’ve found nearby. To add even more concern- I’ve noticed that sometimes the car can get into a very rough idle- RPM drops to 350-400 range and the entire car shakes while the engine seems to choke. Happened twice so far, both times after a longer drive (1hour plus) and after shutting the engine down and firing it up again in a span of 5-10 minutes.

Could those two issues be related? The chocking happens with or without the VSC light present (lights up with the P0340), the VSC and P0340 happen mostly when I step on the throttle with a bit more authority.

Hope some of you fine LS430 owners can point me in a direction I haven’t thought of

 

Perhaps it has something to do with the PCV valve and hose? I checked mine recently and the hose was completely collapsed. It appeared that the hose that was installed had a tube within a hose. The inner hose was completely collapsed. Mine seemed to “breathe” better after swapping out with a piece of hydraulic hose I had laying around. I ordered new PCV and the proper hose.

Another thought, perhaps there is something up with the emission system, like the O2 sensors. My Bank 1 and Bank 2 downstream are both showing up as not working. Considering that this will impact the fuel mix it could be confusing the ECU. I do wonder if the VSC can trigger if there is issues with the O2 sensor’s given that if the engine ECU cannot check proper fuel mix from the O2 sensor, it will set a fixed mix ratio that tends to fall in the rich side. I had my 194,000 miles 2004 LS430 running on tech stream last night. I get P2757 and the codes associated with my O2 downstream sensors. It tells me that the TCC solenoid is the issue. But I’ve suspected that is not the true problem as I have had it diagnosed by a transmission shop and I have run active test with tech stream to monitor the solenoids turning off/on as well as line pressure. I’ve read that those O2 sensors are so durable that often times they will start to fail but still function to a degree when the error codes “fly under the radar”. Preventative maintenance calls for modern 02 sensors to last approximately 100,000.

Hopefully someone can chime in with more insight.

I do see in my vehicle history if service at Sewell , that they had several issues with the VVT and had replaced some components like the charcoal.

I have looked all up under the car and noticed that the wiring harness behind the alternator showed some damage. I had a power steering fluid leak and it melted hoses and wires below it. Part of a wire was exposed on the passenger side plug that goes back to the downstream O2 sensor.