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david, Auto Service Technician
Category: Car
Satisfied Customers: 1500
Experience:  Certified Master Technician,Certified in diesel & gasoline engines
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check engine light on, code p1349 miss at idle & low volt

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check engine light on, code p1349 miss at idle & low volt at bank 1 o2 sensor, also vsc light on      1999 es300 aprox 161000 miles

Hi thank you for your question hope this helps.


DTC P1349 is "VVT (Variable Valve Timing) System Malfunction (Bank 1)".


VVT system controls the intake valve timing to the proper timing in response to driving condition. ECM controls OCV (Oil Control Valve) to make the intake valve timing properly, and, oil pressure controlled with OCV is supplied to the VVT controller, and then, VVT controller changes relative position between the camshaft and the crankshaft.


Here is how this system works. There is an oil control valve on each cylinder head that directs oil flow through the cam and adjusts valve timing.


There are 2 possibilities here as to what is happing. One is that the controller on the cam is physically stuck.


The other is that the oil control valve is in the wrong position (either stuck or activated in error.)

In most cases it is possible that you are experiencing an oil gelling (sludge) build up in the engine.


Simply check under the oil cap for what looks like sludge and check the dipstick for something that looks like a varnish on the dipstick.

If this is the case, you will need some pretty extensive engine repairs performed by a qualified technician familiar with Lexus engines to remove the build up of gelling (sludge) .


If this is not the case, you could be looking at a couple of other things.

The last time I saw this exact condition actually ended up needing a computer.

The ECU was commanding the oil control valve on at various times when it should not have been, like at idle.


The first thing to do is to unplug the the oil control valve connector on the front valve cover, then start the car and see if it idles any better.

Repeat this for the rear one if needed. The procedure I am looking at for this code states that P1349 specifies the front (left) cylinder.

If this solves your problem, you will most likely be looking at computer to repair this problem.


If it does not, you will need to have a technician with a Toyota diagnostic scanner check this system, as it will require the oil control valves to be commanded 'on' by the scanner. You may need to replace a faulty control valve,

Don't condemn the other one if it checks out OK.


Always fix whats broken, not the same part other side just because. You would be wasting your money.



hear is a pic of a vvt valve mounted in the valve cover



Hope this helps

Good luck

Customer: replied 7 years ago.
what about the low voltage showing at o2 sensor ?

I would say it is related to the miss fire. this would put unburnt fuel into the exhaust and the o2 sensor will read it as retch recondition.


I would start with the Variable Valve Timing code,
then if the o2 is still acting up go from there.


Good luck

Customer: replied 7 years ago.
we unpluged vvt , car seems to run good. which fix is most likly ? if you state ECM where is it located ?

Yes if the engine soothed out after unpluging the vvt valve then the problem is in the ECM.


The ECM in mounted under the hood passenger side fire wall



Hope this helps

Good luck

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