Greetings.
2001 LS430 with 193,000 miles. I bought it 6 months ago. I have been going through it fixing everything, including camshaft seals while doing the timing belt.
that was 2,000 miles ago. Now, I am getting the P1349 code. So I tested the OCV and it tested good. I replaced both L and R OCVs, verified proper timing, fixed some weak wiring going to both OCVs and even started engine with L OCV out of vehicle just to blow out oil in case of a clog.
I did an engine flush with synthetic oil at the same time as the timing belt. Everything checks. However, I am still getting the P1349 code every time.
No other codes are present. Can anyone help? What and when should voltage read if I back-probe? If pulling the #1 cap bearing again, what to look for? If disassembling the VVT gearing, what to look for? Thx.

 

OBD II fault code P1349 is a manufacturer specific code that is defined by car makers Toyota and Lexus as “Variable Valve Timing System Malfunction Bank 1”, and is set on these applications when the PCM (Powertrain Control Module) detects a failure, defect, or malfunction in the VVT (Variable Valve Timing system on Bank 1. Note that Bank 1 refers to the bank of cylinders that contains cylinder #1 on V-type engines.

Although there major design differences between variable valve timing systems in use by different vehicle manufacturers, the function of these systems are largely the same, regardless of the application. In fact, all variable valve timing systems have two things in common, these being that a), retarding or advancing the camshafts relative to a fixed base setting can change the engines’ volumetric efficiency to produce more power at some engine speeds, and b), that changing the volumetric efficiency of an engine lets an engine develop more power, while reducing emissions and using less fuel, at the same time.

As a practical matter, the variable valve timing systems on Toyota and Lexus applications uses pressurized engine oil to activate an actuator that is attached to the intake camshaft. When the VVT system is not in operation, the valve timing operates at its base settings. However, when the system is activated, the PCM commands a control solenoid to open, which causes a metered amount of pressurized engine oil to act on the actuator. This in turn, causes the camshaft to rotate either with, or against its normal direction of rotation, which has the effect of either advancing, or retarding the phasing of the camshaft relative to a fixed, base setting.

Which direction the phasing is changed to depends on both the current operating conditions, and control inputs such as large throttle inputs. Nonetheless, when the system is activated, the practical effect is that the altered camshaft phasing causes the intake valves to open sooner, or to stay open longer, both of which conditions improve the airflow through the intake manifold and runners. This in turn, improves the mixing of the air and fuel, which in its turn, improves combustion and reduces emissions.

 

I kinda figured it worked that way. But your detailed explanation really cleared it up. Thank you. However, how do I diagnose and, ultimately, fix P1349 if it is NOT the OCV?
btw, I just back-probed the OCVs and appx 6v at idle and 3.5v at 4500 rpm on both sides.

 

Unfortunately you'd need a scope to check and see what the waveform looks like to see if it is being commanded properly.

https://charm.li/Lexus/2001/LS%20430...0Charts/P1349/

If you clear the codes does the code show up instantly?

In that link I posted above a ways down it shows how you can check the OCV operation by disconnecting the harness connector and then applying battery voltage straight to the OCV. The idle should get really rough or the car might even stall. If that's the case then you know your OCV is working as it should. You'd then want to trace the wires from the ECU to the connector pin to make sure the circuit is intact or not have a break somewhere causing intermittent loss. Also how are your harness connectors to the OCV? I've replaced mine as a lot of these connectors are becoming so brittle from heat cycling that the pins could simply be not seated in the connector and not making connection to the OCV.

 

 

I will look into the video.
yes, I replaced both plugs for the OCVs.
I do not have a scope, but I did back-probe both OCVs today and got the same voltage readings on both sides. So I was reasoning that since I only have the code for Bank 1, then bank 2 is working correctly. And if it is, and voltage from bank 1 matches bank 2, I was assuming voltage was NOT the issue.
so Not voltage, the valve itself, or timing belt off a tooth. I am running out of reasons.

 

Also, per your attached manual instructions, how do I drain the oil from the VVT Controller Assembly?

 

I don’t know if this helps, but I also get a knocking sound on cold startup. Kinda like a collapsed hydraulic lifter. But LS430 doesn’t have hydraulic lifters. The knock goes away in a second or two. Like it is being pressurized with oil.

 

Unfortunately I don't know how you would drain the oil from the VVT controller. I don't really understand how that would work. As for knocking I haven't really seen/heard about VVT rattle on the UZ motors, but can't say that it doesn't exist. I'd say disconnect the OCV and jump battery positive to the the OCV while the car is idling to make sure it's responding correctly. If that checks out then it would just be a matter of the ECM or wiring unless in some way the valve timing or VVT gear timing itself is off. I don't think it's your problem as usually it's a separate code, but the ECM measures the change in cam timing by using the VVT sensor that would be mounted on the side of the head. It's just slightly under the intake kind of in between the injectors.

https://charm.li/Lexus/2001/LS%20430...tion%20Sensor/

This will give you the locations and testing procedures. It's a little bit annoying to deal with, but no need to remove manifold to get to it.

 

I will check out the VVT Sensor.
if only the sensor itself is bad, would it still generate just the P1349 code?

 

Update.
the VVT Sensor checked out at 1,100 ohms. (835-1,400 ohms).
However, the plug completely disintegrated in my hands. At least 8 separate pieces.
The EGR system plug right above it did the same.
so I cleaned up the mess and plugged it directly in without the plug and it seems to be working. No more knocking on cold startup and, so far, no codes. I will need to drive it first.
Does anyone have a recommendation on where to go to buy replacement electrical plugs for the LS?

 

Connectors are widely available from both Lexus and Toyota dealers.
The VVT sensor appears to be 90980-10947 but double check that with a dealer.
The part number starts with 90980-xxxxx the last digits will identify the correct part. The last 5 can also be found on the connector itself.
Also, 430's don't use EGR so you'll have to correctly identify the part in question if you can't get the number from the old connector.

 

I'll have to look at my notes when I get home. I cross referenced a whole bunch of OEM connector part numbers with http://www.corsa-technic.com this is where I've been buying all my replacement connector housings.

I think the VVT sensor codes only get thrown if it's detecting completely out of range or an open circuit, but it's using those sensors in correlation to the Crankshaft position sensor to determine advance or retard of the Intake cam. So theoretically an intermittent or weird connection could cause erratic readings that aren't enough to be out of range, but enough to say the OCV isn't doing it's job without throwing a code for that sensor. Hopefully this is just your issue.

Also looking through my FSM for my 02 I found the procedure to drain the oil from the VVT and it's literally just turning the VVT gear left and right to push oil out of it. This just seems to be to make sure the oil is out before you pull the cam.

 

So more bad news.
the crumbling connectors are not the issue. Although, I did find them for $3 at Rock Auto.
I test drove the car, and as usual, after the 3rd drive cycle, I got the P1349 code. Officially, it is 2 Pending P1349 codes plus the actual active code.
so then I tried the recommendation of disconnecting the #1 OCV when the car is at idle and jumper it with 12vdc. The OCV did energize but the engine rpm did NOT change. I tried both polarities, but that shouldn’t matter either way.
So I think I have localized the problem to internally within the camshaft cap #1 and into the VVT itself.
so next will be to once again pull the valve cover as well as the entire timing belt and take apart the VVT and associated stuff and look for failures/blockages.
Does anyone have any other options or suggestions or what to look for?
This is getting way beyond frustrating. But thanks everyone for the help.

 

The only other thing would be to try energizing the OCV valves outside and make sure they're actually activating. Unlikely, but possible that you have two bad ones.