reozone

This is more an FYI post since I believe I may have finally solved my problem. About a year and a half ago, the “Check VSC” warning message started to come on in our 2001 LS430 (now at 245k miles). It seemed intermittent at first but then just stayed on. My research at the time indicated that, since I had recently read diagnostic codes, I may have inadvertently triggered the message. To be honest with you, I can’t remember what came first: reading the codes or getting the VSC error message. Regardless, I forced the VSC test by jumpering the TS and CG pins on the OBD connector as I had read to do. Magically, the error went away and the VSC started working again, just in time for another winter in Eastern Ohio. Meanwhile, my wife started to complain that the Lexus (her daily driver) ran rough at idle every once in a while. This past spring I did a timing belt/water pump replacement and popped in some new spark plugs while I had things apart, thinking that would fix things. Well, it ran better, but the rough idle still happened every now and then. VSC message continued to plague us and would be reset every now and then but always came back with what appeared to be increasing frequency. I was driving the car about 2 weeks ago when it began running rough again. I ran diagnostics and found two codes I had never seen: P1351 and P1354. Research indicated they were related to valve timing with the OCV as the most likely culprit. At that point, my internet research first indicated a possible link between the OCV and the VSC. I ordered genuine Toyota replacement valves online and replaced them the other day, reset the error codes, reset the VSC, and hoped for the best. Well, it’s been 4 days now and everything seems perfect. There appears to be some mysterious link between the VSC operation and the OCV. In addition, the VSC started malfunctioning many months before any error code related to the OCV was generated. Any Lexus/Toyota experts out there who can explain this? It really doesn’t make sense to lose VSC capability just because your engine is starting to run rough.

Tom57

The Vehicle Stability Control (VSC) appears to be a companion MIL to other malfunction codes. With nearly identical mileage as yours on my '01, 2 weeks ago, I had rough idle, VSC Off and engine light on. Codes showed passenger side OCV. Replaced it. Then, a few miles later, same symptoms with VSC Off light and on-board diagnostic warning lights. This time, codes showed driver's side OCV. Replaced it. Been running fine for several miles now, with better performance and improved gas mileage. (My experience suggests that the OCV valves should be replaced together, since they continuously adjust valve timing for each bank of the V-8. Others here have had similar experience.) Your P1354 code indicates you replaced the passenger side (Bank 2) OCV. Be prepared for rough idle to return soon, VSC Off light, and MIL codes including P1349. Don't get discouraged. This would simply mean Bank 1 (Driver's side) OCV is faulty, another easy DIY fix. (Part # 15340-50011).

Why the VSC Off light? I have had the VSC Off light on other occasions, for example, when a brake light switch (under the brake pedal) was faulty and ABS sensor issue - why it seems to be a companion light to other core issue(s). Your OCV must've been intermittently faulty, causing periodic VSC Off light and throwing codes. The codes could go away after multiple starts and mileage if the OCV was working properly, then return again when the valve acted up.

reozone

TOM57, thanks for the input. I did replace both banks at the same time for the exact reasons you are stating. Hopefully, I will not be plagued by another VSC malfunction for a long time. We put another 250 miles on the car today without any issues. I'm feeling pretty confident. Also, about a year or so ago, we did have a problem with the brake switch, which I also replaced. Maybe that's what started it all.

Tom57

Glad to hear you are trouble-free again, reozone.

The earlier brake switch issue is unrelated to your recent issue with OCVs. (Smart you replaced both of those critical valves.) You could get another VSC Off light down the road, but it most likely won't be from the OCVs.

kentgs300

Glad you got it sorted.

Having had some issues with my other car a Citroen C5. It was doing the same thing when an exhaust differential sensor did not work properly and was putting the car in limp mode. The stability control would not function. The car was a diesel.

From what I gather, it is purely when the torque of the engine is sacrifised and the engine cannot operate properly, then the VSC will be turned off.

You have to remember the VSC is not working only on the brakes. But it also will cut back on the spark, throttle. In order to regain control of the car should anything happen.
When the timing on the car is not working correct and the computer cannot get proper readings, the VSC will go off. Either wise the car could do anything it likes.

Yours was a tricky one initially without any relevant code.

Boomer01

Both of mine went bad this year about 8 months apart. I've had no problems or error messages since replacing them. It's an easy fix too.

burteboy

The VSC light appear whenever the MIL is on. Because you should have the vehicle check asap by an authorize dealer or tech.

bmore430

Have any of you who have replaced them, care to do a separate thread explaining the procedure or a How-To thread with part numbers or links to where you purchased, parts needed, tools etc?

I'm sure many of us will run into this issue and having to replace them so it would be helpful.

Thats what this forum is all about.

ijones027

Hi my car ls400 1998 recently started to shake at idle, and the codes I get were p0300, p0301, p0303,p0305, my mechanic told me it's the control oil valve but I changed it less than 1,000 miles ago if anybody can please advise thanks

Tom57

There are a few existing threads for replacement of the oil control valves. It's a very easy DIY (one hold-down bolt for each OCV). The plastic wire harness clip which attaches to the OCV gets very brittle so removing that without snapping the clip is really the most difficult part of the job. Here's an existing thread revealing the codes that are associated with driver- and passenger-side OCVs, engine symptoms, and OE replacement part numbers, as well as a clear diagram from the shop manual (provided by rkw) > https://www.clublexus.com/forums/ls-...g-at-stop.html .

ijones027

Update from yesterday my car stopped shaking. But later tonight it started shaking again and now in the inside the middle part of the dash shakes at high speeds if anybody can help thanks

rkw77080

Your mechanic may have given you the wrong information on the DTC's. For Toyota vehicles, P0301 is for misfiring in cylinder #1, P0302 is for cylinder #2, and so on. If you have misfiring in more than one cylinder, you will also get P0300 for random misfiring. A word of caution - continue to drive with severe misfiring will cause overheat in your catalytic convertor.

Attached is the troubleshooting procedure for a 2001-2003 LS430. I cannot tell you if the procedure applies to your LS400. That said, we know that you're experiencing misfire on cylinder #1, #3, and #5 (all on the same side). The troubleshooting procedure suggests to check valve timing, fuel pressure, mass air flow meter, and engine coolant temperature sensor. Of those, I would start with fuel pressure since your problem cylinders are all fed by the same fuel rail.

tradosauru

I found the part numbers on RockAuto listed under Variable timing solenoid.

Tom57

There are two oil control valves (OCVs) on your V-8 > one for each bank of cylinders. They should both be replaced. Replacing only one typically results in the same engine shake. When the oil control valves failed on my '01 LS430, I had codes P0300, P0301, P0303, P0305, along with P1349 (driver's side OCV).

ijones027

Thanks for the response I dint get the last code of p1349 and I replaced both ocvs with in the past 8000 miles