Britprius

Just staying with Vredestein they show there winter tyre ratings as Econ (C) Wet grip (C) Noise 70db. There summer tyre same size Econ (B) Wet grip (A) Noise 70db. A substantial improvement in wet grip. There figures not mine. John.

Perhaps surprisingly winter tyres do not offer as much wet or dry grip as summer tyres at above 7C. I can see the advantage of only running one set of tyres, but you would be better off saving the winter tyres for the winter, and fitting some summer tyres for the months that are generally above 7C. Below 7C winter tyres win hands down. John

Strangely the tyres I am testing are "Three A", and as yet I cannot fault them, and better than the Yokohama's. My next set of tyres "in about 2 tears time" will probably be Landsail. With ratings of "B" for wet grip, "A" for fuel economy, and a noise level of 69db on the 245/40/18 size. I would be interested in the ware rate of these if you have any information? As you say tyres today are manufactured in many different counties including the top names being made in India, China, and Malaysia. John.

I would never buy part worn tyres, but I am also not a tyre snob. There are some very good "cheap" tyres on the market, and some very bad expensive one's. People tend to believe if your paying a high price they must be good. There are some tyres called "Landsail" that were tested against some of the so called top tyre brands by a German tyre test company. The Landsail tyres held up in all respects coming in third place in 20 brands. I am testing some cheap tyres at the moment, and I am currently nearly half way through the test. I can say without doubt the tyres I am testing would exceed most peoples expectations for wet, and dry grip, handling, and although still at limited millage the ware rate appears very good. I would rate them above the Yokhama's that were taken off the car. Yes there are some bad tyres out there I agree, but they are not always the less expensive tyres. A few years ago makes such as Kumho, and Hankook were frowned upon. Now they are there with the other so called best. John

Robert. Have a look at this page it may help. workshop-manuals.com/lexus/gs_450h/v6-3.5l_(2gr-fse)_hybrid/maintenance/brake_bleeding/system_information/service_and_repair/page_2010/

If you have not already done so I would really recommend you try bleeding the brakes before buying another brake accumulator. Remove as much of the original fluid as you can from the container before refilling it with fresh fluid. Then flush through plenty of fluid remembering there is a bleed screw on the accumulator it's self. John.

Maybe, but the GS450H has problems with it's transmission oil pump, and only cost circa £2600 for a new unit, and all through lack of suitable lubrication. Sealing the pump motor and allowing the transmission fluid into it would have resolved the problem or fitting slightly more expensive "pennies" full complement bearings. So much for brand reputation. Replacement bearings cost around £7. John.

Most readers will read engine codes, but few will read codes for the hybrid system, and others such as key fob, and TPMS that can be reached via the OBD port. Reader based on the Toyota Techstream system are the one's to look for. John.

I believe with a hybrid vehicle where the are high voltage "700 volts" electric motors with the winding's in the transmission oil it is a good idea to change the oil after the first 10,000 miles " to remove any ware in metal parasitical's", and then every 30,000 miles to remove possible acid build up. Metal in the oil is not only abrasive to the conformal coating on the motor windings. It is also conductive giving the possibility of winding short circuits. Oil also tends to turn acidic after periods of use also not good for electrical insulation. Electrical transformers are often oil cooled, but even this oil with no mechanical mechanisms working in it is changed periodically because of acid build up. On the Prius forums it has long been found that after the first 10,000 miles of use the oil comes out black. After this period at 30,000 miles it comes out comparatively clean, but has lost much of it's viscosity. For those hybrid transmissions that also have clutches or brake bands the material shed by both the linings and the drums must also have a detrimental affect. The use of the correct oil is also a must with the hybrid. Many oils will have the correct lubrication properties, but not all will have the desired electrical insulation properties. John.

Try pulling the fuse for the headlamp washer pump. That should do the trick. John

Yes one of the strange behaviors of the hybrid on long downhill runs is. Once the battery is fully charged putting your foot on the brake makes the engine speed up, and putting your foot on the accelerator makes the engine slow down. The reason being once the battery is fully charged to 80% the computer cannot allow more energy to be put in so it uses MG2 acting as a generator to power MG1 acting as a motor to spin the engine without fuel to use the energy. Putting your foot on the accelerator uses electrical energy to power the car instead of spinning the engine so the engine slows until a given road speed is reached when it stops completely. John

Has anyone noticed if you turn the car off, and leave it for a period of up to an hour or so when returning to the car it drives very readily in electric mode almost irrespective of the battery state of charge. Battery life is affected by a number of circumstances the main two being the number of charge discharge cycles, and excess heat. Forcing the car to run on electric cycles the battery unnecessarily, and uses more fuel. The Toyota/Lexus hybrids are petrol vehicles. That is all the energy that propels the car comes from petrol. Charging the battery from the engine involves a number of energy state changes all of which involve losses. Burning fuel to produce mechanical movement is about 40% efficient. Not much we can do about that, but drive the wheels. However if we choose to charge the battery from the engine:- Driving a generator to turn mechanical energy to electrical energy produces a loss. Changing electrical energy to chemical energy "charging the battery" produces a loss. Changing chemical energy to electrical energy produces a loss. Changing electrical energy to mechanical energy "electric motor to drive the wheels" produces a loss. So discharging the battery by forcing the car to run on electricity uses more fuel because once the battery is discharged the engine not only has to power the car, but also charge the battery. The thing that makes the hybrid more efficient is capturing energy from costing "foot off the accelerator" and braking using regeneration to charge the battery. Energy that in a normal car is discarded. This energy can then be used to help accelerate the car back up to speed. This is the time the engine normally uses the most fuel. Maintaining speed uses comparatively little fuel. Using the Hybrid in this way means the battery is only cycled in very shallow charge discharge cycles. The shallower the cycles the longer the life. The battery use by the cars computer only allows for a maximum charge level of 80%, and a discharge level of 40%. This is to greatly extend the life of the battery compared to running at 0 to 100% charge/discharge cycle. John

I have now covered a little under 4,000 miles on the tyres. While it would still be unfair to give an accurate assessment on the ware rate "appears to be good" I can say the tyres are quiet, but not the quietest tyres I have used, grip well in both wet, and dry conditions, and give good steering response. This information is based on normal road use on mostly rural roads with no motorway use, but lots of spirited driving on the sort of roads enjoyed by "Big Rat, and company". I am not saying they are track day tyres, but good value normal motoring tyres. The tyres replaced a set of Yokohama's with around 5mm of tread, and compare favorably against these in all respects. I am now prepared to name them even though I have not reached 5,000 miles, and this is where I expect to get shot down in flames. The tyres are made in China and are Three A brand P606 rated for M&S but not winter tyres. Price expect to pay £55 around each fitted, and balanced for 245/40/18's. I am not in any way connected with the tyre company or it's sales just an honest opinion on the tyres I have tested at as yet limited millage. Any further developments good or bad will be posted here. John.

The actual single fan motor loading at full fan power is 1.4 amps or 18 to 20 watts less load than a stop light. Running the fan at say 10 watts would give efficient cooling with little fan noise. This when the theoretical GS450H battery capacity is around 2000 watt hours. Connecting an adjustable stat in series with suitable resistor across the existing battery sensors would turn the fan/s on at a predetermined ambient temperature without upsetting the existing battery temperature monitoring. The resistor could be adjustable allowing for fan speed to be set as well as temperature turn on point. John.

I have often thought that the hybrid battery cooling systems use the wrong criteria for turning on the cooling fans. As things stand the fan or fans are turned on by battery temperature, but this is a bit of shutting the stable door after the horse has bolted. The fans not coming on till the battery is already warm or hot, and even then they turn on running slowly increasing speed as the temperature goes up. The battery cell core temperature will be much higher than the outer shell. Surely it would be better if the fans were turned on by ambient temperature cooling the batteries before they get warm. The sensors are fitted on the under side of the modules meaning the core temperature can have risen considerably before they turn on the fans. On certain models of the Toyota/Lexus hybrids "the Prius, the CT and possibly more" it could be argued that using the AC helps cool the battery as the air intake is in the passenger cabin meaning cooler air is used when the AC is on. Of course the energy being drawn by the AC must offset this to an unknown degree. Of course the battery temperatures should be taken into consideration, but early intervention when ambient temperatures are high must help in keeping temperatures down. I think we are lucky in the UK that our climate is reasonably moderate compared to parts of Europe, and the US where heat is a major factor in early battery deterioration. John.

Hi Lucas. I am sure Richard will put things right for you. For clarification the reason I say there is no kick down is that the GS hybrid along with all the other Toyota derived hybrids until this year "things have changed from now" is that the vehicles only have one gear ratio, and further it is permanently fixed in this ratio. It has no reverse, and no neutral. Everything is accomplished electrically buy varying the speed, direction, or if the electric motors are being supplied with current or producing current as a generator or allowed to spin freely. Even engine starting is done with the same motors. There is no normal starter motor or alternator. So you cannot kick down into another ratio that does not exist. John.

Having previously had a Prius with the same screen, and camera along with all the lines ect I cannot fathom the GS either. The Prius had auto parking "look mom no hands", but this seems to be missing in the GS? John.

All green bars showing is a charge level of 80%. The cars system will not allow more than this. Descending hills or long downhill inclines can easily bring it to this level. No bars at all showing is a charge level of 40% the lowest the system will allow. There is no danger in either scenario. The situation to avoid is leaving the car in ready mode, and neutral. In this situation the car cannot manage the charge level in both the HV battery, and the 12 volt battery. The engine cannot start in neutral "it can continue to run if it is already started", and can therefor not maintain the charge in the HV battery. If the AC is left running this can quickly discharge the HV battery. The HV battery in turn is used to charge the 12 volt battery through a DC to DC converter "no alternator". If the HV battery is discharged it can no longer charge the 12 volt battery so this also becomes discharged. John

Hi Lucas. As your probably aware POA7F is the code for battery deterioration, and POA80 is the code for replace the battery. The best advice I can give is to contact LOC member Richard "Hybrid battery solutions", and discus the problem with him. There should be sub codes pointing to the modules in the battery that are week. The reason you are getting the fault on full acceleration "there is no kick down" is that on full acceleration the battery is fully loaded using the electric motor drive for maximum acceleration. John

Sport mode will put a big smile on your face, but do not turn off traction control in the wet in sport mode as you will likely end up facing the wrong direction. John.

Sport mode drastically alters the throttle response it also alters the steering ratio, and marginally stiffens the suspension.. Hybrid power does not in my opinion make much difference. John

The only thing I have to go on regarding system capacity on the GS is again the Prius. It was recommended to have 4 ltrs or a gallon to hand to change the fluid completely. I would remove as much of the old fluid in the car by using a turkey baster "new one" to draw off the fluid in the container to start with John.

In Techstream go to the brakes ECU choose flushing or bleeding brakes, and it walks you through the process. John.

Bleeding the brakes using Techstream does a better job at changing fluid in areas of the system by opening hydraulic valves via the ECU for fluid to pass through. This on the Prius "which uses a similar brake system" has been known to clear low pressure problems by removing small dirt particles stuck under valves. Worth a try anyway as the fluid should be changed I believe every 2 years. John.

If it is asking for a code you have loaded the software in the wrong order. You must load them in the order quoted in the instructions on the disc. Remove the program in "control panel- programs & features" then reload in the correct order. If I remember correctly the drivers first without having connected the cable. Then the program, and finally connect the cable. Connecting the cable first makes windows look for suitable drivers, and it loads an incorrect version. John.