Britprius

I should have added to the above that there is a limit to how much "engine braking" can be used. To much risks locking up the rear wheels thus loosing control. This is because "unless you have the 4 wheel drive version" engine braking can only be done via the transmission to the rear wheels. If any slip of the rear wheels takes place engine braking is either removed or severely reduced till all wheels rotate at the same speed. Not doing this would mean severe oversteer "the rear of the car overtaking the front in a spin". John

If the traction battery is fully charged the so called engine braking is minimal. The reason being the energy produced by the motor generators has no where to go so the engine revs just rise.There are no separate gears as such for any purpose including reverse. See my thread in the GS450H forum entitled "How the GS450H transmission works". Any gear is purely an electrical state of the motor generators. John

On my car it has plastic covers under the engine and gearbox. Also side panels covering the floor pans, and rear of the car. John

For those that would like to know how the GS450H transmission works I recommend looking at the link shown below. It shows how the engine and motor generators work to give the the apparent variation in ratios. You can play with the sliders to give various speeds, forwards, and reverse. Showing the engine variations in RPM at different speeds. Note MG1 can run in either direction and change direction depending on driving conditions. It shows there are no actual gear changes even for reverse or neutral. The nomograph near the bottom of the page is actually for the Prius so the revs and speeds will be different, but the principle and method used mechanically is the same. http://eahart.com/prius/psd/ John

I will check my car underside tomorrow and report back. John

Your description of the fault is a little confusing saying (quote) "When the car tries to start now there is a horrible grinding noise from the transmission tunnel area." Then "it now appears to start and run fine." The 12 volt battery is nothing special. It does have a temperature sensor that can be removed, and fitted to the top of a replacement. This sensor helps control the charging voltage for the 12 volt battery. Can you get the car into ready mode? Put the car in drive with the parking brake off holding the foot brake firmly on with your left foot. Then apply some accelerator. The display should show the traction battery charging. This is called force charging, and is safe to do as all the engine power goes to MG1 (motor generator one) to provide a charging voltage. John I agree with you on the transmission pump theory. That was going to be my next suggestion. Generic scanners will not work on Toyota based vehicles. I suggest you buy a "Mini VCI" from Ebay or Amazon as with this you will be able to read all codes.

Your description of the fault is a little confusing saying (quote) "When the car tries to start now there is a horrible grinding noise from the transmission tunnel area." Then "it now appears to start and run fine." The 12 volt battery is nothing special. It does have a temperature sensor that can be removed, and fitted to the top of a replacement. This sensor helps control the charging voltage for the 12 volt battery. Can you get the car into ready mode? Put the car in drive with the parking brake off holding the foot brake firmly on with your left foot. Then apply some accelerator. The display should show the traction battery charging. This is called force charging, and is safe to do as all the engine power goes to MG1 (motor generator one) to provide a charging voltage. John

I do my own top ups using "Rothenberger" plumbers pipe freezer spray. This is available at B&Q, Wicks, and Screwfix. It is the correct pure refrigerant with no oil. You will need to make up your own delivery system. If all the pressure has gone you will need the services of a professional. Toyota or Lexus dealers are the only people I would trust with this apart from AC only service places. John

I do not know if this applies to the GS450H, but the Prius "still uses the same basic hybrid system" requires at leased 3 gallons of fuel put in if it is run out of fuel. The computer does not allow the car to start until this amount is put in. So one gallon may well not get you going.

Be very aware that the ATS guy does not use equipment that has been used on non hybrid cars. This can cause contamination of the special oil (ND11) used in the hybrid electric compressor. Normal AC systems use PAG oil. This conducts electricity, and once even a very small amount of it gets into a hybrid AC system can and will cause high voltage leaks in the electric compressor motor shutting down the car completely. This may not happen immediately, but will some weeks down the line. The reason for using dye is so that it can be seen after the gas has escaped under ultra violet light.

The car will always run on the engine until the cats warm up. This is to reduce emissions. The battery even when showing only one bar of charge is still more than 40% charged. The minimum charge with no bars showing is 40% charged the minimum the cars computer will allow under normal circumstances. When all the bars are showing this represents a battery level of 80% charge. Again the maximum the computer will allow. If you run out of fuel and continue to drive on electric this can reduce the battery level to a point where the car will no longer start. This means an expensive trailer lift to the dealer for a recharge to a level for the car to start.

The battery modules shown have a manufacturing date of 24/October/2011. The code reads first two digits = day of month. 24th day Next digit is 1-9-x-y-z = month of year. X=10 (October) Next digit year is A starts 1999. M=2011

You can check if the Apsss is working by removing a front shock absorber top cover, then remove the actuator " simple quarter twist". Turn car on, and have a helper turn sport switch on and off. You should be able to see the actuator drive tube move a quarter turn each time. John

Sport mode definitely stiffens up the suspension. Most noticeable when I am towing my caravan as it cuts out the wallowing on uneven road surfaces. It sharpens the throttle response "very noticeable at any time". Alters the steering ratio, and stiffens up the front anti-roll bar. John.

I ran a set of the Goodyear Efficient Grip Performance on my Prius. Although grip, comfort, and noise were very good the life of the tyres were very poor at only 18000 miles down to the ware bars. At this point a sidewall decided to call it a day. This is something I had been warned about before buying. The car had no tracking or suspension problems the tyres Waring evenly across the tread. The Hankook tyres that they replaced lasted for 42000 miles before a piece of steel on the motorway put an end to two of them. They would have lasted to 45000 miles easily.

The white "fixing" is just holding the wire in place it provides no electrical connections.

The GS battery is not a deep cycle AGM battery. It is a normal flooded lead acid battery. Varta, and Bosch along with others make a 70 AH battery that is the same size for circa £50 with a 4 year guarantee. AGM (absorbed glass mat) are used where the battery is in the passenger compartment "such as the Prius" so that in case of damage to the battery in a collision there is no free liquid acid that may splash on to occupants. The only requirement is to tape or heat glue the temperature sensor from the old Panasonic battery to the top of the replacement battery. This sensor adjusts the charging voltage slightly dependent on battery temperature. Most batteries are today made with one or more vent outlets. All lead acid batteries should have battery temperature monitoring as part of the charging system, but few vehicle manufacturers bother as it makes very little difference.

Coming from a Prius without the SKS system I do find it strange to have to put the car in park before being able to turn it off. With the Prius system pressing the start/stop button with the car stationary instantly puts the car in park, and turns it off. I sometimes still forget to shift to park, and just press the stop button. This does not shut the car down correctly, and unless the parking brake is applied the car will roll.

The reason the car still drives without the fob being in the car is a safety one. If the fob battery goes flat while you are driving the car could cut out on the fast lane of a motorway or anywhere as the car would loose detection of the fob. This is common to all the Toyota keyless start systems. If the battery does go flat in the fob. The car can be started buy holding the fob close to the start stop button while pressing the button. If you leave any car running you are asking for it to be stolen, and are also committing an offence " leaving an unattended vehicle running". Your insurance will not pay out.

D2-R/S bulbs run at around 85 volts. The R is for reflector S for projector. D4-R/S bulbs run at around 48 volts at near double the current of the D2 bulbs. The ballast in the Lexus is designed for that voltage "48" so the correct bulb is D4S. The starting voltage for both bulbs is in the 25,000 volts range, and needs treating with respect.

I bought my 2007 GS450H eight weeks ago. I have had the recall notice from Lexus stating that the work will take 4 hours. After discussions on the phone concerning my distance from the nearest dealer in Wolverhampton, "I live in Hereford" they have agreed to a loan car for 2 days while the work is carried out along with a safety check, and hybrid system check.

If you have the car serviced by Lexus or Toyota "as you intimate" after the initial 60,000 miles guarantee the battery can be under guarantee for up to 10 years. This is irrespective of miles driven. With each service a hybrid check is carried out "free of charge" and the battery guarantee is extended by 1 year or 10,000 miles up till it's 10 birthday. In your case this could mean the battery is under guarantee till 300,000 miles. I have just sold my 8 year old Prius with 124,000 miles with the battery still under guarantee.

A tricle charger will do only good to the 12 volt battery. It would also be a good idea to make sure the HV battery is in a high state of charge when the car is turned off. If not force charge it till it has high blue or all green bars on the display. Do this by leaving the car in park and in ready mode, and putting you foot on the accelerator forcing the engine to run. This may also be done in drive with your left foot firmly on the brake.

I agree with John above, but perhaps surprisingly the two narrower sizes suggested are actually more expensive tyre for tyre. I find this is often the case. Tyre cost depends on the numbers sold or manufactured. My last car was a Prius with oem size tyre of 195/55/16 going up one size to 205/55/16 the tyres are 25% cheaper for the wider tyres. 245/40/18 tyres for the GS450H at my tyre supplier go from £38 to £178 per tyre. (all new tyres correctly rated)

The inverter charging system is common among all the Toyota/Lexus hybrids. The GS450H has another inverter running at 40 volts to provide power for the power steering. The AC also runs from the traction battery via a variable frequency 3 phase inverter to power the compressor drive motor. This ensures the AC works when stuck in traffic with the engine not running.