Britprius

There must be a supply for the ignition coils, Or perhaps better still the fuel pump. John

No the trigger for solenoid is timed it only opens for a few seconds at ignition on or may be in the case of a hybrid after first cold start, it could be triggered by the engine run signal. This could easily be arranged. John

In the case of restarting when the engine has already bean running there will at the instant of starting be two oil supplies plus the oil in the system will not have totally drained back to sump. The cars own oil pump and a supply of oil at a pressure that is the maximum that the engine runs at. "The stored pressure". With both supplies the rate of oil flow at start must be doubled halving the "un-lubed time". Using 0w20 oil also speeds up the process. John.

In one of my previous post I mentioned the fact that I was "and still are" thinking about fitting a pre-lube system to remove the annoying rattle from the VVT system. The system is very simple using a sealed pressure bottle which is fed with oil from the bottom through a solenoid valve. When the engine is running, and has oil pressure the pressure of the oil compresses the air in the bottle as it fills. When you press the start button an ignition feed opens the solenoid for a few seconds allowing the oil under pressure to travel round the engine. Because there is a delay before the engine starts in a hybrid the engine will have pressure before it turns. Once up and running the oil will flow back to refill the bottle "ready for the next start" even though the solenoid is closed because the solenoid only shuts off in one direction of flow. This would allay any fears of lack of lube at startup, and also remove the VVT rattle. There is such a system ready produced on the market, but it would be very easy to make your own system. John. www.ebay.co.uk/itm/Auto-Engine-Pre-Lube-Oiler-Tank-Could-Save-Your-Engine

It is not the oil pressure that keeps components apart it is just the presents of oil that counts. In many small 4 stroke engines and all 2 stroke engines there is no oil pump. In the case of 2 stroke engine the oil is mixed with petrol. John

Yes the system is very clever at fooling us into thinking we are using different gears when in fact it is a clever balancing act by the computer controlling the two MG's to give the impression of gear ratios. Even the traction control is performed by this operation. John

I should have added to the above MG2 the traction motor becomes a generator every time you take your foot off the accelerator or put you foot on the brake. This is used to slow the car down by generating electricity and returning it to the battery. John

The above shows just how simple the hybrid transmission is. Never at any time is there an actual gear change even for reverse or neutral. The GS450H does have a single gear change planetary set on one electric motor to reduce it's revs at speeds above 60mph. All of the Toyota/Lexus hybrid transmissions have two MG's, but only MG2 is used for traction. MG1 is used for engine start and as a generator to supply the battery or MG2 with power depending on conditions. Four wheel drive systems such as in the RX use another motor built into the differential to drive the rear wheels. There being no mechanical link from the engine to the rear diff "no prop shaft". When braking the diff motor turns into a generator for regen braking on the rear wheels. John

If it is the same as the GS450H it is up near the brake pedal. So you need to stand on your head to see it. John.

This is due to the reversal of use of MG1 (motor generator one) while starting the engine it is being used as an electric motor, "tens of times more powerful than the normal starter motor" but immediately the engine starts it turns "or more accurately it is switched" into generator mode to supply more electricity to MG2 "the larger of the two motor generators in the transmission" along with the battery to help drive the wheels. Below is a link to a nomograph of how the system works. Scroll to near the bottom of the page and move the sliders to show how engine speed and the two MG's work together. Note MG1 will run in both directions depending on conditions. This is for a Prius, but the systems used in the Lexus are the same. .http://eahart.com/prius/psd/ .

When you lift your foot off the accelerator nothing is powering the car. On the display you will see green arrows going from the wheels to the battery "green for recovered energy that would normally be lost". The electric motors turn into generators and put electricity back into the battery. In doing this actually slows the car down in the same fashion as any other car slows when decelerating, but with other cars the engine is pushed round wasting energy. With Toyota/Lexus hybrids the engine stops completely. The engine ware due to stop start is minimal due to the facts that, the engine is still hot, the oil does not have chance to drain down in a short period, and the engine does not start at low revs with little oil on the bearings. The engine is run up to 1500 rpm in milliseconds by one of the electric motors then fuel and ignition is applied making for a very smooth start. John

If it has variable valve timing? Yes. John.

Perhaps an alternative to this is is a computer auto on energy saver multi adapter. This plugs into the mains, and you plug your computer "or tv" into the adapter. When you turn on your computer "or tv" it turns on the other outlets on the adapter. These would normally be for powering other computer peripherals, printer, scanner, ect, but in your case the sound bar. Turning off the tv will remove power from the sound bar. John.

I have now found the front side light fuse after much searching. It is located in in such a position in the under bonnet fuse box that it is almost invisible. Towards the front of the fuse box the is a separate box with four fuses laid on there sides with the tops just visible until you pull this box upwards out of the main fuse box allowing access to the fuses. It is one of these fuses that controls the front side lights. I will add a picture shortly. John.

When the HV battery is empty the engine is forced to idle to charge the battery. The filters are easy to get to once the engine covers are removed, and only require one spanner to remove the tubular bolts that cover them. They can be washed out in petrol as they are made of plastic with a fine mesh. Dirty oil would soon block them reducing the flow through particularly at low engine speeds. Use 0w30 or 5w30 oil or even 0w20 as I do. The 0w20 oil may be more expensive, but in my opinion is well worth the extra with the faster cold start lubrication it provides along with better fuel economy. John.

The GS450H AC is electric because the car is a hybrid, and the engine is not always running to power the AC. This is fairly strait forward, but it is essential you remove the high voltage safety link on the HV battery in the boot to remove any risk of electrocution. When refilling the system only ND11 oil can be used. PAG oil used in non hybrid systems will produce a code for a high voltage ground fault. Equipment that has been used with PAG oil should not be used even with the correct ND11 oil This will then require another pump, and a complete AC flush. The GS430 is not a hybrid, and therefore the pump is driven by the engine probably by a serpentine belt. This makes it more difficult to get at. The system uses PAG oil on refill. I give both systems because the OP's avatar says he has a GS430. John.

The code relates to the crankshaft or camshaft position sensors. The fault could also be caused by the camshaft timing oil feed filters being partially blocked. There are two of these small filters located on the side of the cylinder heads near the front. Each camshaft timing unit is fed with oil through an aluminium pipe running up the side of the heads terminated onto the head with a banjo style bolt. The filters are under this bolt. The filters can be removed and cleaned but new ones are not expensive. This would be my first port of call since the problem appears at low engine revs "when there is likely to be lower oil pressure" Cleaning the crankshaft and cam shaft position sensors might also clear the fault. John.

See the thread improving GS450H low beam.

I have now installed 55 watt D2S bulbs with suitable ballasts. The results in my opinion is it is well worth the effort giving an improvement in brightness estimated at about 30%. At the moment I have fitted the ballasts, and wiring in a temporary fashion "not wishing to dismantle the front of the car to change the ballasts until the system was proven" by removing the bulb access round covers fitting the 55 watt bulbs and wiring through the access points from the new ballasts. I have removed the OEM ballast fuses, and picked up the feed for the new ballasts at the fuse points. The bulbs used were cheap Chinese 55 watt D2S bulb at £12 the pair and some equally cheap Sun Wolf 55 watt ballasts that I had lying around. I would not recommend these ballasts as they run very hot, but for test purposes are fine. The light output is now I believe what it should have been. Lighting the road well with an identical beam cutoff to the OEM bulbs. This modification does not produce a large increase in light output, but does make an appreciable difference to night driving. I have had no flashes from on coming traffic. All that now remains is to dismantle the front end of the car to make the mod permanent, or alternately I "may" drill the bulb access covers and take the wires in through those with suitable grommets. This would allow the OEM system to be reinstalled easily. John.

I could not agree more concerning the choice of tyres for noise levels. Coming from a Prius to the Lexus was a revelation noise wise. However the OEM tyres on the Prius were Bridgestone's , and changing to Hankooks reduced the noise level considerably while also improving the mpg figures in spite of the fact that I went from 195's to 205's. I now pay great attention to the tyre labels for economy, grip, and noise level. I have also learned the higher the price you pay for tyres does not always translate into a better tyre. John.

When you brake the electric motors are turned to generators turning the vehicle kinetic energy into electricity which is returned to the HV battery "regeneration". It is the whine from these motor/generators you are hearing. This slows you down without using the normal mechanical brakes, and saves fuel by allowing the energy normally lost to be reused. When coasting there is a small amount of regeneration to give a mild braking effect that you get from a manual car when you take your foot off the accelerator. John The GS450H has the motors "2" in the gearbox driving the rear wheels. The RX has motors in the gearbox driving the front wheels, and a motor in the differential that drives the rear wheels. The rear wheel drive is electric only in the RX as the differential has no mechanical link to the engine. John

When you brake the electric motors are turned to generators turning the vehicle kinetic energy into electricity which is returned to the HV battery "regeneration". It is the whine from these motor/generators you are hearing. This slows you down without using the normal mechanical brakes, and saves fuel by allowing the energy normally lost to be reused. When coasting there is a small amount of regeneration to give a mild braking effect that you get from a manual car when you take your foot off the accelerator. John

The only other item on the front that could cause a rotating bump noise would be a wheel bearing. On the rear again wheel bearing or drive shaft. The microphone idea works very well. A single earphone or bud type earphone on an alligator clip serves very well as a mic. John

John. I have a 2006 GS450H. The front tyres ware very evenly with no noise other than on very smooth painted indoor car parks where the tyres squeal at any speed from just moving to around 30 mph when maneuvering forwards or reverse. I have not been above that speed on these surfaces for obvious safety reasons. The rear tyres ware very squarely wearing the centre of the tread first even though I tend to run the rear tyres below recommended pressures. The tyres on the rear ware at about twice the rate of the fronts on my car. The bump noise does sound like a tyre problem or buckled wheel "unlikely". As has already been said try swapping round wheels. A system I often use in situations like this is a microphone fastened to the suspension at various different points plugged into an amp inside the car with the volume turned up. This will usually pinpoint the noise. In my Prius I used the cars own audio in through the JBL sound system sadly missing on the Lexus ML system. John.

The battery is at about 50% state of charge with2 purple bars showing. However running on the battery with no fuel will take the battery to a level where the engine will no longer start. This can also happen if the car is left in neutral with the AC left running as the engine cannot start in neutral to keep the HV battery charged. This has a knock on effect on the charge to the 12 volt battery as this receives it's charge via a dc to dc inverter from the HV battery The computer does not let the engine start when the HV battery is discharged to low to protect the battery from cell reversal, and this is well documented on the Prius forums. The Lexus CT200H uses all of the Prius drive system. The battery self discharge rate is so slow that batteries that have been stood for 5 years have still maintained enough charge to register on the bar graph display, and start the car. Any bars showing on the display shows a charge level of above 40%, but not more than 80%. This is the range that the system is designed to work in to give long battery life. John.