Hayne

Have you tried turning off the air con compressor, but leave the climate control on? Could be related to a faulty temperature/pressure sensor for the air con system (maybe) Clutching at straws, but worth trying. Giles.

Are you sure that its the ABS actuator module at fault? if Lexus told you its the brake booster, then are you sure it's the same part? My understanding of a brake booster is the circular donut shaped assembly with a vacuum diaphragm mounted to the engine bay bulkhead behind the brake pedal which boosts pressure to the master cylinder. The faulty solenoid could be related to vacuum regulation. Just a thought. I'd hate for you to buy the wrong part. It's just worth checking with Lexus that you are looking at the correct part. Giles.

Interesting issue. That doesn't sound like correct operation to me. My GSh temperature doesn't budge once it's up to temperature, even when coasting down a long hill in cold weather. Engine temperature rise will take slightly longer than a conventional petrol car due to the high efficiency of the simulated Atkinson cycle engine, but the sound of fans coming on could be something else; you have a lot of stuff going on under the bonnet relating to the Hybrid system that may sound like a fan. If the mechanical thermostat is working correctly, then it is unlikely that continuous fan run would cool your engine like that without coolant running through the radiator. As Ganesh suggests; push this back to Lexus. Giles.

Hi Andrew, Yes, it is now fixed. See the thread titled 'GS450h Loss of Power' for full details. Has your pump stopped operating? Giles.

Interesting point; I too would like to update my sat nav software and maps as they are a few years old now. I used a supplier a few years ago for software and maps for my BMW745i. It cost about £30 for a full disk set. It all worked too and gave me 7 digit post code entry. I will have a look back in my emails and PM you with his details. A 7 digit post code function would be nice if Lexus have released it for our cars. Giles.

Hi Pete, I am not 100% sure, but could it be to do with the user settings referenced to the keys? If you are changing settings under one user name and the key is linked to a different user, it may change the settings back when you use that key. I have never used this function before as we only use one key between us, but its worth a look in the manual. I believe this also changes the seat position settings too, depending on the key used. I hope this give you some ideas. Giles.

NX300h? That's a huge step-down from your beautiful £100k super-luxury car. It's a shame you're having this problem with your engine, but dealers are so pressured to perform that they are sometimes too quick to diagnose and can end up repairing a non-fault. Your problem is probably something very simple, especially at your very low mileage. Any Lexus should be able to do around 200k without major mechanical work being carried out. I am seriously considering a LS600h next (although my GS450h is an excellent car and I am very happy with it). It will be interesting to see if they can correct your fault this time. Good luck.

Yes, when an air lock is present in the coolant supply to the regulator, the vaporiser freezes when the liquid LPG expands into gas. This can cause a split regulator diaphragm (I too have experienced this). Luckily for you, you have a new regulator, but in future, the internal diaphragm can easily be replaced if it happens again.

Hi Tony, Lovely car. Didn't you trade in your broken GS450h for a Mercedes? I seem to recall you had a failed hybrid transmission pump. Giles.

Well spotted. I've had several LPG converted cars in the past and I found that generally, LPG converted coolant systems are harder to bleed than unconverted cars. I had a V8 Range Rover once where the only way to bleed it was to use mains water pressure from a hose pipe sealed onto the rad and let the pressure bring all the air and water out to the expansion tank (with the cap off). Worth noting or the future, maybe.

Something worth checking; When I repaired my transmission oil pump last week, I noticed that there are four jubilee clips clamping the heat shields to the exhaust section around the cats. (2 each side). All four had broken and there was some rattle on start-up until the exhaust had warmed up slightly. Its worth checking that this is not your rattle, first of all. They only took me a few minutes to fit and they were about a £1 each. Worth a look.

Yes, very valid points Colin, but I would have thought that Lexus would have a fleet of long term test cars that would have many, many miles on them to test for early failures ( this is just an assumption) so it is possible that they picked this one up before customer's cars started to fail. I would have thought that all manufacturer's would do this to save on costs with recall management and reputation. Still, if revisions weren't to do with bearing failure, I wonder what it could have been? I expect we will find out in due course.

I should also mention what to look out for when your pump is due to fail. These are my experiences; About 2 months before my hybrid transmission oil pump failed, I particularly noticed a slow response when the gearbox changed the CVT torque multiplier ratio (i.e. equivalent to an overdrive gear). About the torque multiplier: At about 55mph, the gearbox changes the ratio of the CVT to the high ratio (you will notice a short drop in power of about half a second) before continuing to accelerate. When decelerating below 35mph, the torque multiplier changes to the low ratio (again, you will notice a short drop in power/engine breaking, while this changes). At this point, if the pump bearing is worn, the change is slower. This is most noticeable under hard acceleration, where the change can take a couple of seconds due to the pump motor struggling to turn properly, causing slower pumping of the transmission fluid (it is worth experiencing this now so you know what to look for in the future). I experienced a couple of times, the dash displayed the message 'Hybrid System Overheating' during hard acceleration. This too, was the pump failing to supply enough pressure to change the torque multiplier ratio in time. To try and overcome this just before my pump failed, I began taking my foot off the accelerator at around 55mph, just to give the pump a chance to supply enough to change ratio. About 2 months later, while driving in electric only mode, the pump bearing seized and caused the car to grind to a halt, as there was no pressure. If this does happen to your car, don't panic, just power the car off using the power button, then power on, wait for the READY light to go steady (takes about 10 seconds under the fault condition), then drive away as normal. The car will just be running in petrol engine only mode. The dash will show 'Hybrid System Fault'. The car will not drive at above 75mph. I drove my car with this fault for 5000 miles before I repaired it. So, to summarise; if your car changes the torque multiplier ratio quickly under hard acceleration at about 55mph (could be up to 75mph, depending on acceleration), then the pump is functioning correctly. If you notice slow changes, or the overheating message, its worth replacing the bearing anyway. I hope this will give GS450h owners a little more confidence as to the state of their pumps and what to look out for. PLEASE NOTE; THIS IS JUST A SUMMARY OF MY EXPERIENCES AND MAY NOT APPLY IN THE SAME WAY TO YOUR CAR. Giles.

Thanks for all the comments and support. I hope it will be of help in the future. As Ganesh suggests, I shall write a 'how to' guide and post it in the next few weeks. When inspecting the pump, it noticed it has been well designed for reliability and, in fact, the pump and motor are very simple and should last hundreds of thousands of miles due to its single moving part (the shaft with magnet assembly). As there are no brushes there is little to fail. Even the motor shaft position sensor is simple by design and easy to access once the motor has been disassembled. The sensor is an array of hall-effect switches (magnetic flux sensing) and is easy to rework. The 2 most likely failure points of this motor assembly (in my opinion) are the bearings and the output shaft seal. The failed part is just a bearing, and bearings do wear, as we all know. There have been 4 revisions of this motor assembly since it was released in 2006 (my late 2007 model still being the 1st release) so Lexus have obviously known about failures and have made revisions to try and overcome this. I don't know what these revisions are, but I expect that the front shaft bearing was made larger/higher quality. So, the point being that I don't see any real benefit of buying a new pump when the design is so mechanically sound (apart from the bearings!!!). If your pump fails, it is very likely to be this £7 bearing. Giles.

Likewise. Mine sounds the same for less than a second, but it appears that its only when cold. It has never worried me as it runs like a sewing machine at all other times. It has 160k now. Giles.

Hi Robert, I have just completed this procedure today on my GS450h. It is very simple to do. There is a sump drain plug (14mm bolt I think) and then a refill plug on the side of the gearbox and a level plug just below it. Drain your ATF and then put the plug back. Remove both the fill plug (upper) and level plug (lower). Fill with ATF from the top plug hole and it starts running out of the lower hole, you know its full. It took 4.5 litres on mine. Run through the gears then check the level again, and you're done. Should be a similar procedure with yours, but mine is a different box being a Hybrid CVT transmission. I believe that the drain and refill holes principle is the same. Giles.

REPAIRED FOR £7 !!! Hi all, I have finally repaired my transmission oil pump on my GS450h !!! After many months of 'trying to find time' to repair it, I finally got the car on a ramp today. Firstly drained the ATF fluid from the gearbox (approx. 4.5 litres came out). I them removed the exhaust bracket mounted on the gearbox (4 bolts). Then I unbolted the oil pump (4 bolts) from the gearbox and unclipped all the connectors from the oil pump controller and wiring mounts from the chassis and fed the cables back from the engine compartment to the gearbox area. I then checked out continuity of the wiring from the connectors to the pump. All were fine. Next I removed the pump housing from the motor and inspected the shaft by trying to spin the shaft on the output of the motor. It was seized. I tried moving it with some mole grips and the shaft moved, but grated. I then took the pump assembly apart to look for brushes (had to drill out 3x M5 screws as they were seized on), only to find that it is a brushless motor with 3 coils, like a stepper motor. I checked out the front shaft bearing and found that it was worn, causing the shaft magnets to grate against the motor coil assembly. Bingo.!!!!! Fault found!!!! I then visited my local bearing specialist and, hey presto, he had the correct bearing in stock! I also purchased the rear bearing too, just as a matter of course, totalling £14 in parts. They are only little 22mm bearings, and are common parts. Then I started to reassemble the motor with the new bearings. I had to drill out the 3 M5 screws completely and re-tap the threads to M6 and fit 3x new M6 screws in place. I then reversed the removal procedure and then filled the gearbox with ATF. I started the car. The same Hybrid fault came up. So I plugged in my code reader and cleared the P2797 code, and HET PRESTO. NEXT TIME IT WAS STARTED, THE CAR RAN PERFECTLY. I now had full Hybrid functionality and a fully wrking car. I am ecstatic. and extremely pleased with myself. Considering Lexus say the only remedy is a new oil pump at the cost of £3240. I have fixed it for £7. All in all, it took me 5 hours to repair (not including finding a bearing supplier). Lets hope this is good news for all of us GS450h and LS600 owners (same pump on both cars). Regards, Giles.

Does the car seem to accelerate normally if you manually select the gears using tiptronic? If not, then there is nowhere for the power to go except to the wheels, so it maybe engine related. Unless your torque converter is slipping (i.e. worn lockup clutches or faulty lockup solenoids). Its only a thought, but the power has to be going somewhere if the engine is working ok. if it is engine related, maybe your fuelling system is not supplying enough pressure to the fuel rail (i.e. faulty FPR, fuel pump fault/seal leak). Also, I have had a throttle body gunked up which caused a sticking butterfly. I once had intermittent power problems on a Volvo and it was found to be a faulty MAF. I replaced it and all was fine. Just a few ideas to think about. I hope you manage to find the fault ok. Giles.

Sorry to hear your fix didn't work. You would think that Lexus would have diagnosed this correctly, so not sure what went wrong there. Well, at least you have done it yourself and at least you can try and sell your old pump controller and probably get most of your money back. It sounds like your pump may be at fault. The fact that the car starts with the same fault message as mine, makes me think it could be the same thing. I am still investigating the pump issue on my car. Last week I put it on a ramp to see if I could remove the pump motor. It looks very easy to remove the pump assembly (only three bolts), but the motor is fitted with bolts which are only removable when the pump assembly has been removed, but the ATF has to be drained first, otherwise it will spill out if removed. So, as I need to drive the car daily, I drove it home with no work carried out. The next stage is to buy some transmission fluid (Toyota ATF-WS) and go back to the ramp. I will then drain the ATF, remove the pump assembly, connect the power wires to a 12 volt supply to see if the pump motor turns, check that the pump is connected to the motor shaft (i.e. not sheared off, or a worn spline). If the motor turns, then it is likely to be the pump position sensor (which could relate to a fault on the pump controller). If the motor doesn't turn (my preferred outcome), then I will remove the motor from the pump assembly, then refit the pump back to the car and refill with ATF, so I can still use the car. Then, I will check out the motor to see if it has burnt out, or just has worn brushes. I will then send to a local guy who re-winds motors and see if he will tackle it. Hopefully, the outcome may help you too. Going back to your car, I have seen the VSC messages come up too. The first time was at pump failure. The only other time it does it is if I select 'Drive' before the READY light comes on. I take it you are waiting for the READY light to go steady before you put the car into drive? This takes about 10 seconds from pressing the power/start button. Otherwise, may be you have 2 faults; the other relating to the VSC computer (stability control), which I think is related to the ABS, but not sure. Another thing to try is to go onto JustAnswer and post a question to a seasoned Lexus Master Tech who may be able to help. I did this a couple of months ago and he gave me some diagrams and some good advice, giving me a way forward. I only cost me about £13. Worth a try. Giles.

I have never had this issue, but since my Hybrid system failed, the car still goes like stink and the power needle still goes pretty high up the range, so I haven't noticed a huge difference at the top end. The Hybrid power is limited to about 50bhp when the engine power is at full power (about 290bhp), therefore if the Hybrid system wasn't transferring all of its power, its only about 15% of the power anyway. At low speeds (i.e. from standstill) the hybrid system really makes a difference. My car is much slower at initial take-off than it was before Hybrid failure. To conclude, in my opinion, I think it's more engine related than Hybrid. Maybe your MAF needs cleaning; I had a similar issue with a Volvo a few years ago. This also seemed low on power sometimes then had full power the rest of the time. Turned out to be a faulty MAF. Note: if you do end up changing the MAF, do not buy an aftermarket one, as these are not worth the money and don't work. Only buy an original manufacturer's part. Again, I have had experience of aftermarket MAFs!! I am not saying that you have a faulty MAF, but its a good starting point. I hope that gives you something to think about. Giles.

Hi Komain, That's very interesting. It seems odd that the car is intelligently limiting and reducing your speed as you drive. That is a different fault to mine as my car comes up with the fault message and just drive perfectly normally, but without Hybrid. I have heard that the pump controller can fail. Luckily for you, they are readily available from breakers yards, whereas the gearbox pumps are not easily available as pump removal means loss of transmission fluid, therefore an incomplete gearbox. Im my opinion, I would buy a used pump controller and fit it yourself ( there is one on ebay uk for £150). at least if it doesn't solve your problem, you haven't spent $1200. I don't know if the controller needs coding to the car, but probably not. It also looks fairly easy to replace too, as you can see it in the engine compartment. Very good luck with your repair. Please let me know how you get on. If it works, its a cheap fix! I haven't had time to look at mine further yet, but I am going to my local garage on Thursday to buy some ramp time so I can continue my investigations. I'll keep you posted. It's hard finding time what with work and kids! Giles.

Barry, that's a very interesting comment. My Hybrid system has stopped working due to a transmission pump performance fault code, pointing to failure of the electrical auxiliary transmission oil pump. I am looking at the possibility of repairing my pump myself (I am a firm believer that everything is repairable!) but seeing your comment regarding old transmission fluid has made me think. My car has done 160k miles, so is probably well overdue for a change. I will buy a few litres of ATF and give it s go. In your experience, does this sound like a feasible possibility that feedback from the pump flow rate sensor could cause an error like this with old oil? Thanks. Giles.

Hi Paul, They are fantastic cars being very comfortable and very fast having awesome acceleration. They are very well loaded with toys too. I love my GS450h and I'm very happy with it, apart from my issue with a transmission pump. It is basically a petrol engine'd car with an auto gearbox and a Hybrid system strapped to it. The engine is very strong and reliable, the only issue I know of was relating to valve springs. This was due to an assembly robot being out of tolerance causing a scrape mark on the springs creating a weak spot causing it to fail over time. Mine has done 160k now and there are no oil leaks whatsoever, no knocks or unwanted sounds and the engine runs smoothly and pulls like a train, just like a new one. The gearbox is also very strong and is an award winning design. It is the smoothest gearbox you will come across due to its continuously variable transmission and has the added advantage of fast acceleration as the virtual ratio ensures that the engine is at maximum revs during hard acceleration with no actual gear changes, giving it a 25% acceleration advantage over conventional auto gearboxes. It is a wonderful piece of engineering and I believe it to be reliable over many high miles. Its weakest point appears to be the auxiliary transmission pump for the Hybrid system which pumps transmission fluid round the gearbox when the engine is off (the gearbox has a mechanical pump for when the engine is running). I am currently investigating my issue with the failed pump in another thread, but if it fails, the car can still be driven fine, just without hybrid functionality. The pump costs about £900 to buy and is not a huge job to fit on a ramp. The traction batteries are another potential weak point. There are about 40 nickle-metal-hydride batteries in the boot of the car, which cost about £4000 to replace. You will NEVER need to replace a £4000 bank of batteries (although I'm sure Lexus have made people replace them all in the past). You only ever need to replace the faulty cells at a cost of about £120 each. Of course, there will be some diagnosis time too, but people with basic knowledge of vehicles can test batteries. Another weak point is the Hybrid inverter. I don't think that this is too common a fault, but used inverters are readily available for about £1k to £1k5. I read somewhere that there is a GS450h with 350k miles on the clock and no major surgery. Other than that, it has pretty much the same mechanical parts as any other V6 GS. Don't let the weak points put you off buying one though. Just don't go to a main dealer if it goes wrong. I have had BMWs and Audis with poorly engineered design faults that make the Lexus seem very well engineered by comparison. I don't visit main dealers, but spend time on the web looking for information about faults, and come to my own diagnosis most of the time, making ownership a lot cheaper. I hope that helps you with your decision. In my opinion, they are excellent cars. Take the good advice from Tony and Ganesh too; they have owned their cars longer than I have. Regards, Giles.

Ahhh, I didn't read the last 2 pages of the thread before posting a reply. Sounds like you have traded it in for an E-Class now. Good luck with your new car. Giles.

Hi, I am having the same issue with my GS450h (see my thread near the top of the list). I am still driving the car as normal, but without Hybrid. My car too ground to a halt when the pump failed, but when I restarted it, the hybrid fault message was displayed, but the car drove perfectly. Have you tried re-starting the car and driving it? When you press the power button, it does a self check, finds the hybrid oil pump is not functioning, then starts the engine. This process takes about 10 seconds every time you start the car, but you get used to it. Just don't put the transmission into 'D', until the READY light goes steady (if you do put it into 'D' while the READY light is flashing, it will cut the engine (due to the self-test failing) and you will have to restart it). In my opinion, go back to the Lexus dealer, start the car and test drive it. I think you'll find tht you will just drive it home as normal. The transmission cannot be damaged by driving the car without the oil pump running, as this is only controlled as required so isn't on all the time anyway. I'm affraid that main dealers are not competant at repairing cars without looking into the techicalities of why a car isn't working or a part has failed. They are under such pressures that not enough time is spent properly investigating issues, which is why I always investigate matters by myself before coming to a satisfactory conclusion. The main dealer is very wrong if they say you need a new transmission when the pump fails. This pump is a separate part which is readly available from Lexus and other suppliers on the web. And it's relatively easy to replace too!!! In relation to Tonyrocha's comment above, the pump is not located inside the gearbox. It is mounted on the lower offside of the gearbox in full view. You can see it and it's mounting bolts, even without removing the transmission plastic cover. To conclude, don't loose hope yet and certainly don't scrap the car, just because a little pump has failed. What's the worst that can happen; you still have a beautiful car but without the Hybrid economy (I am getting 28mpg over the last 2000 miles without Hybrid functionality). There is a limitation to not having a working pump - the overdrive gear will not operate, so you car is limited to 80mph (I know, I tried it and lost power while overtaking at over 80mph, then investigated why). This is because the CVT hits its maximum possible linear ratio at 80 mph. You basically have a 2-speed auto gearbox with a continuously variable transmission (not a six speed gearbox like most people think, as the so-called 6-speeds are vitual gears selected by an ECU controlling the CVT ratio). Anyway, enough of my waffling (I could go on for hours). Let me know how you get on retreiving your car and watch my other thread over the next few weeks. Hopefully we can both have working pumps soon. Giles.