Thackeray

Interesting that the manual says the TPMS must be reset if the tyres are rotated. Can someone explain why this is? It may be that later models than mine have a different system but I thought the sensors inside the tyres simply transmitted an ID number and the tyre pressure to the car. The car can then report the pressure for each sensor to any device that can read it. (On the dashboard it just puts up a warning light if any of the pressures are too low.) But how does it know which corner the tyre is on unless an installer has identified the location of each sensor? If it's just a radio signal from the sensor to the car, how can this be affected by moving the tyre from one corner to another? And if it can't, why is there any need to reset the system after tyre rotation? Can anyone provide enlightenment?

Sorry to digress but the estate version of the 940 was the perfect family car. A built in child booster seat in the middle of the rear seat and the "Celebration" end of production model came with a metal, fold-down, suitcase/dog guard grille to partition off the load space from the passenger area. Compared to a 220D, though, its acceleration was probably fairly unimpressive. I expect the mpg was unimpressive too but at 1990s prices nobody really knew what mpg their cars did.

Look at the minute by minute fuel consumption monitor display. Typically, I see around 20 mpg for each of the first five minutes while the engine warms up. It then starts to move up to around 40 or more on longer journeys. But in the winter it takes around 7-10 minutes to get up to normal temperature and the low mpg continues during that time. There was a period when I was doing short journeys - four miles there, wait four hours during which the engine cooled down, then back another four miles. I was getting little more than 30 mpg during the winter, with all the accessories turned on - heated seats, headlights, wipers, screen demist etc.

Well, that seems to be 11 people in this thread who use Faraday pouches, one who doesn't dare in case the key gets stuck inside a locked car and one who uses the function built into some keys to disable them. (As Herbie points out, not all cars do this.) I've puzzled over this too. Initially, I thought it was great just to walk up to the car and open the locked door, just by having the key in a pocket. But when parking in busy places, I began to do what Brian R does, except that I press the lock button twice to double lock the doors (you can't open it from the inside if, for example, the window is broken.) Then on the second press of the lock button I do the double-press of the unlock button and get the four red light flashes to confirm it's disabled. But recently on the NextDoor website I've seen half a dozen reports of cars stolen from driveways or outside a house and I've now adopted the habit of double-locking the doors and disabling the key every time. Now that this is a habit, I don't even think about it. It's not much different from older remote locking systems. Occasionally, in remote areas, I might decide not to bother but mostly the car is left double-locked and the key disabled. The habit saves thinking about it. However, this represents a significant failure of the Lexus attempt to make getting into the car easier. This is a pity. All that clever design gone to waste. I hope they come up with a system that's actually usable on new models and at the same time prevents the car from being stolen, without having to resort to buying addons from ebay. The other thing I initially thought was great was that if you open the boot by pressing the boot button on the key fob, when you close the boot it locks again and the doors remain locked - there's then a steady red light on the dashboard to show it's locked and the alarm is on. But what I forgot for some time was that when I press the key fob button the key becomes enabled again, even though the doors and boot are locked. So even when just unlocking the boot I realised I had to disable the key again before abandoning the car to the attentions of the criminals.

If this happens in my area, it's generally a mini-cab driver waiting for an early morning pickup for the airport. It needs to be early for the first flight to Brussels (EU meeting), Eurostar to Paris (lunch with clients), train to Coventry (company sales conference). But the driver is five minutes early so they have to fill in time. It's an IS300h so when the car is stationary the engine is not running but the air conditioner repeatedly whirs and then stops (the electronic noise?) Bored, the driver notices a newer but almost identical car and is interested to see how it's different from his/hers and so gives it a closer look. Still filling in time, it would make sense to drive further into the estate and turn round to be ready to set off when the customer appears. This is usually the explanation if there's only a driver in the front and the car is fairly luxurious. If there are two people in the front it's plain clothes police staking out the area. But they're in a Ford not a Lexus. If it's criminals, they're also not in a Lexus - more likely Mercedes or BMW with blackened windows.

There's a button in the glove box to disable boot unlocking. You can't open the boot if this button is activated.

The Mercedes design was interesting. As you applied the foot pedal it made a clicking noise as if a ratchet was operating. In fact, the noise was made by a plastic clicker to make it sound like a ratchet. If the plastic clicker broke, applying the brake would be silent. Instead of a ratchet the brake was (perhaps still is) applied by pulling a cable between two sprung mounted rollers. When the cable was taut the springs would clamp the two rollers together to prevent the cable retracting and this would hold the parking brake "on". Apart from the tendency for the plastic clicker to break, the other problem was that the cable would tend to get sticky on its route to the back wheels. So when you pulled the handle to release the parking brake, it didn't fully release and the brake pedal didn't revert back to its normal upward position. You could use your foot to pull the brake pedal back to its upward position but this resulted in annoyingly scratched shoes. The standard make-do-and-mend fix for this problem was to attach a spring to the brake pedal itself to pull the pedal back up to its normal position when you pulled the release handle. By contrast, the Lexus foot-pedal feels much more robust and better designed.

My guess is that the problem in the design results from Japan using a different type of digital radio system. So they don't really understand how the British DAB system should be set up for the user and they haven't bothered to find out.

Services should alternate between major and minor each 10,000 miles or 12 months. Extra on the major service is brake fluid and differential oil. In addition, at 60,000 miles spark plugs should be changed. But this is by distance travelled not by time. So at 51,000 miles the spark plugs are not yet due. It would be worth checking on your invoice whether they have been done. If they have you could either complain or you could just accept that they've been done and don't need changing for another 60,000 miles.

The dashboard gauge doesn't represent the actual charge of the battery. On the IS300h, the car's computer keeps the charge level no lower than 40%, at which point the engine will start to boost it to 50% and then the engine will stop if the car is stationary. The 40% level is shown as two bars on the dashboard and 50% is shown as three bars. In average use, the IS300h battery stays in the range 50-60% most of the time and from memory, this range is represented on the dashboard as between three and six bars. The battery will go higher on a long down-hill run but the maximum is 80% (eight bars) and at this point the car will start to spin the engine without fuel as a load to prevent the battery charge going any higher or even to reduce the battery charge. It rather looks from this video of the Hybrid Assistant app that the Auris (and maybe the CT?) aims to keep the battery in the 60% range rather than the 50s that I tend to see on the IS but I don't know if that's so or just what was happening on this video. On the video the battery percentage appears at the bottom right of the app's panel. Initially, most people have the instinct that a full battery must be good, like a fuel tank, and a low battery is bad, like an empty fuel tank. But that isn't the point of the battery. The battery is there to store the regenerated electricity produced when braking. If the battery was full, there would be nowhere to store it. Instead, the computer aims to have the battery about half full. Then there's room to store any regenerated electricity but also a reasonable amount of power available to briefly help with acceleration. This is not a purely electric car so the aim is not to have a full battery. As a hybrid, its aim is to recapture energy that the petrol engine produces and then reuse it to improve the mpg.

You may already be familiar with how the DAB radio is supposed to work. But just in case, and before you start taking the car apart, this thread might provide some useful clues.

That sounds reasonable and it may come from more recent research. (What's the source?) I'm afraid I was just spouting from my memory of what the 1933 Oxford Dictionary says. I've now looked it up and just to compare, here's what it says: "From 15th to 17th century spelt tire and tyre indifferently. Before 1700 tyre became generally obsolete and tire remained as the regular form, as it still does in America; but in Great Britain tyre has been recently revived as the popular term for the rubber rim of bicycle, tricycle, carriage and motor-car wheels, and is sometimes used for the steel tires of locomotive wheels."

"Tire" was the usual spelling both in Britain and America in the 19th century and earlier. This was when the only tires were the metal tires on farm wagon and carriage wheels. Then about the time Dunlop invented the pneumatic rubber tire for the recently invented bicycle, it seems as if the spelling "tyre" appeared around the 1880s, probably as some kind of marketing gimmick in advertisements. It caught on in Britain and became the standard British spelling.

Thanks for the explanation. A flat battery is something I can cope with. The way prices are going it may soon be cheaper to buy a new battery than the routine cost of filling up with petrol!

What went wrong? Was it the same thing five times? Or five different faults? It would be interesting to know the details so other owners can watch out for the same problems.

Internal combustion engines deliver maximum power at fairly high revs (maybe 4-5000 rpm) but maximum torque can be delivered at much lower revs. Particularly in a diesel you might be getting maximum torque from maybe 1,600 rpm up to maybe 3,000 rpm. In a manual transmission car, you can get maximum power if you want it by changing down to, say, second gear (depending on the car) at around 40 or 50 mph and accelerating up to 70 mph still in second gear (or maybe third). But this is very noisy and the average driver doesn't really like the noise. So they don't ask the car for maximum power by changing down and instead rely on the torque to provide them with the acceleration. If you stay in third when you want acceleration or even fourth, that's usually enough for the average driver, particularly in a diesel, and it isn't as noisy as changing down to second, which the manual gearbox with fixed gear ratios obliges you to do if you want maximum power. By contrast, the Toyota/Lexus CVT works differently. It can give you any ratio and hence maximum power just by pressing the accelerator. If you press the pedal hard, the car takes it that you want maximum power, which means high revs and of course it's more noisy, like changing down to second. But a manual gearbox can't give you maximum power unless you change down, which most people choose not to do. So in a manual transmission car, if you want to the engine at 4-500 rpm you have to change down a gear or two. In a Lexus hybrid you just press the accelerator.

Is it still doing the same pattern of 1. firing, 2. not firing and screen goes blank, 3. firing, 4. not firing and screen goes blank? If it is, perhaps there is something that can be deduced from this pattern in terms of ruling out certain types of problems. Eg can it fire if the key is at fault? Can it fire if the fuel mixture is wrong? Another question. If it fires at step one, what happens if you wait 10-20 seconds before trying again? Does it do the normal step 2 or does it fire like in step 1?

Just in the interests of pedantry, I hope it's ok if I mention that a translation website tells me that "schiessewagen" means "shooting brake"; you don't see many of those nowadays. Or maybe it was meant to mean something else.

Nothing you do makes much difference as the engine isn't used to propel the car for the first couple of minutes from cold. In the first stage of warming up the engine the car only moves on battery power. You may think it's running on engine power because you can hear the engine. But if you look at the energy monitor you'll see that no power is flowing from the engine either to the motor-generator or to the wheels for the first minute or so. This happens even if the car won't let you switch on EV mode. Below is the description of the first two stages of engine warmup, copied and pasted from the link I included in my earlier post. If this is more information than you wanted, the only advice might be not to accelerate too hard when the car has just started from cold. But ultimately, it's probably not going to make much difference. Stage S1a: when the start coolant temperature is below 40C, the warming up starts and continues for approx 50 seconds after stage S0. you can not enable the EV-Drive Mode during this S1a. the ignition timing is very late, after the top dead center. therefore the engine does not have enough power to drive Prius or charge battery. basically, Prius can not use the engine power when you drive. Prius is driven by battery power and the battery is discharged. it is good idea to drive slowly or stand still warming up in this stage. when the start coolant temperature is between 41C and 60C, Prius is in this stage, but the engine does not start automatically. when you press the accelerator (including driving), the engine starts and runs for approx 50 seconds or until the coolant temperature reaches 65C. the ignition timing is very late too. S1b: this is an extended warming up stage. you also can not enable the EV-Drive Mode during thisS1b on Gen3. (you can enable the EV-Drive Mode on Gen2) the ignition timing is now normal, and the engine is able to provide power and charge battery. you are now ready to drive without any penalty of battery discharging. ( A ) if the the coolant temperature is still below 40C after S1a, the warming up continues until 40C. ( B ) if the the coolant temperature is between 40C and 50C after S1a, the warming up continues until 50C. ( C ) if the the coolant temperature is between 50C and 60C after S1a, the warming up continues until 65C.

If the engine was cold when you started it would have used a lot more fuel than when cruising with a warm engine on a motorway. Switch to the energy display that shows a fuel consumption graph minute by minute. If you watch this when you start the car from cold you'll see that it will be doing around 20mpg for around the first five minutes (or more depending how cold the weather is). But as the engine warms up you'll see the mpg rise to its normal level for the proper engine operating temperature. The engine goes through five phases of warmup which affect engine timing. So the best consumption won't be reached until it reaches the fifth phase, (confusingly this is called stage 4) which on a short trip it may never reach. If you're interested in the engine stages, see this link, and scroll down to post number 7 by "Grumpy Cabbie".

Two things I was wondering. If the engine fires, can the problem be in the immobiliser? Maybe it can, I don't know how the immobiliser is supposed to work. But I would have guessed the immobiliser would prevent the car getting as far as firing. Maybe someone who knows the answer can say one way or the other. The second thing I wondered was about the code for the O2 sensor which controls the air/fuel ratio. Could there be a connection between whatever was wrong with the sensor and the fact that the engine fires briefly and then stops? Initially it looked as though there was a problem with the fuel but maybe the air/fuel ratio might cause a problem. Again, it would be good to rule this possibility out. I assume the rear sensors are only to monitor the catalytic convertor but presumably the front ones contribute data to control the air/fuel ratio.

Me too. I've missed the recent episodes of this saga. What's been happening? I'm wondering if all the work on the car has changed the symptoms or is it still doing the same as on the youtube video back in December? Back then, the car would fire briefly, the dashboard electrics would come on and the engine would stop; at the next attempt the starter would turn but the engine didn't fire and the dashboard electrics didn't come on. Then it would repeat the same pattern of briefly firing, then followed by the starter turning but the engine not firing and no electrics on the dashboard. I'd be interested to know if the symptoms have changed or is it just the same? (See video below.) I'm also wondering about the O2 sensor code. Are there four sensors in this model? Is a fault with one or more of the O2 sensors now ruled out?

Interesting that Autocar says: "In 2020, Mercedes-Benz stopped its long-running F-Cell programme, due to high costs and an inability to lower them." But this "sustainability" website says Daimler (Mercedes) is working on fuel cell trucks in a collaboration with BP, which is planning a 1GW hydrogen plant in Teesside. It says Daimler intends its trucks to use the refuelling infrastructure that BP is planning and aims to begin delivery of trucks to UK customers from 2025. I don't doubt that they may have difficulties reaching their targets but on the face of it the report that Mercedes (by implicaton Daimler-Benz) has given up on fuel cells doesn't seem quite right. And BP has recently announced plans for a second Teesside hydrogen plant. Even if most of this hydrogen is fed into the natural gas network for home heating, it would be a step towards there being widely available hydrogen, which eventually could be used in trucks or maybe even cars.

In reverse these hybrid cars are always (not "typically") powered by electricity. They have no reverse gear as such in the transmission, as a conventional gearbox has. Instead, when the gear selector is put into reverse, the electric motor that powers the road-wheels (Motor-Generator 2 - MG2) is simply run backwards. The engine may run or not, depending on other conditions.

Probably an unusual answer, but I was mostly fascinated by the elegance and mechanical simplicity of the transmission. And on the practical side, I thought the mechanical simplicity would bring better reliability than a conventional car. I've read somewhere that a conventional automatic transmission has around 300 or more parts, compared with just 22 in the first Prius. That's a lot fewer parts to go wrong. The hybrid transmission also means there's no need for a starter motor, an alternator or a clutch because these functions are built in to the basic design of the transmission. Again, fewer parts to go wrong. This is borne out by a Which? report that the CT has the best reliability record in the UK. Las Palmas above also mentioned the reliability of his car. You may already be familiar with how the transmission works but for anyone who isn't I'll add this graphic which I've also mentioned in some previous posts. (Incidentally, ignore the chain final drive in the video. Only the earliest Priuses used a chain for the final drive and I don't think any Lexuses ever did.)