Herbie

Having had a 2005 RX300 I can say with confidence that there's only one battery, that being the one I've arrowed above. The hybrid 450h has two, a 12V 'auxilliary or starter' battery and the high voltage traction battery.

May be a different fuse box because I'm sure mine are labeled as 'Cig' rather than P/Outlet but I could be wrong.

How long is it since you used the car? It's very unusual for the traction battery to just 'fail' without warning and even if the car has been stood and not used for about three months (or even longer) there should be enough charge in it. When you press the Power On or Start button, one of the very first things to happen is that the 12V battery operates two 12V relays that are configured as a safety interlock, which acts as a sort of 'gatekeeper' to the hybrid system. When the interlock operates, it then gives access to the hybrid system but if the battery hasn't got enough power to operate the relays, the hybrid system will not power up. If things are working correctly then the sequence is something like this: 12V battery boots the computers, does a couple of other things and also operates the interlock, which brings the hybrid system online, as shown by the green READY indicator. At this point, given sufficient charge in the traction battery, the car can be driven off on battery alone. When the hybrid system needs the petrol engine, it uses MG1 (Motor/Generator No.1) to spin the engine up to 1,000rpm before supplying petrol to the injectors and applying the sparks to ignite it. As a first move I'd be very much inclined to have the 12V battery load tested (drop tested).

The battery is in the engine bay, as arrowed below: EDIT - Doh! I didn't realise Colin had beaten me to it

You need an auto box specialist not a general mechanic, no matter how good they are. It may be a Lexus but because it's not a hybrid it's just like any other petrol-driven auto. Plumbers for plumbing work; electricians for electrical work; aircon specialists for aircon work and so on.

I'm afraid that that is just absolute codswallop (the board won't let me use the phrase I really want to ) The negative battery post is connected directly to the car body by means of a thick wire and a couple of braided earthing straps. This means that the entire body and any* clean, unpainted, screw, nut, bolt, bracket etc., whether that be at the front, back, top or bottom of the car, right next to or as far as possible from the fusebox, is a suitable point to use as a negative connection. No harm will come to any of the car's ECUs or electronics unless you reverse the polarity of the leads. Even then, the small booster packs have inbuilt reverse polarity protection and should stop anything bad from happening. I write this as a time-served, qualified electrician who, after the factory closed down went on to spend the vast majority of my working life as a telephone engineer and latterly, after a back injury, went self-employed as a computer repair technician. I'm also a licenced radio ham, callsign G7IFM. I tell you this not to be obnoxious or anything but just to make the point that I've been in the electrical/electronic field for more than 40 years and that I do have a bit of an inkling as to how these things work *The only thing to be wary of is that there will be some self-tappers around that only screw into plastic, which is obviously no good for this purpose; anything that screws into metal will be good to go.

As has already been said, either way will work. 12V is 12V whether it's at the front, back, top or side of the car and all you're doing is piggy-backing a known good 12V source onto a dodgy 12V source, so no worries either way

Well in that case, I unreservedly apologise and wish you well with the car.

Disagree all you like Bernard but it won't change my mind. A hybrid car is just SO very different to a conventional one in so many ways. Even the way you drive it is different (if you want to get the best out of it), let alone the technicalities of it. These cars are basically computers on wheels and you wouldn't dream of buying a new laptop or tower without research first. Even some people in these very forums have admitted to not knowing that a hybrid doesn't have a starter motor or an alternator for instance. They've been asking for help to fix a problem, saying that they suspect the alternator and then they're completely gobsmacked to be told that it doesn't even have one! They are attracted to the colour, styling, comfort and other things that we take into account when buying a car, but that's all they're doing - just buying a car. They have no understanding or concept of what "Hybrid" means and how different it is and/or what those differences mean. What makes them think they can just jump in and drive without doing some research, especially on whether a hybrid car will meet their needs and fit in with their driving habits? To take Elaine's case in point (sorry Elaine, I'm really not having a go at you) she states: "We do short, infrequent journeys" which is complete anathema to a hybrid car. Of course, we don't know if Elaine did any research beforehand but, without being nasty about it and not having a pop at her, I would hazard a guess that maybe she didn't? If that was the case it would be interesting to know if she would make a different decision or stick to her first choice? Elaine - you also said: A very quick and dirty calculation can illustrate the problem. The capacity of the battery is measured by the Ah rating on the label. Ah stands for Amp-hours but unfortunately I don't know what the Ah of the battery in the LBX is, although I think someone mentioned 40Ah. This means it can supply 40Amps for one hour, or 20A for two hours, or 10A for four hours and so on. Now, there's always a draw of power from the battery even in the middle of the night when both you and the car are asleep. This is to keep alive things like the clock, the radio presets, seat memory and so on, and it usually measures around 50mA to 70mA-ish. That's 0.05A to 0.07A. If we assume a brand new and fully charged battery and we also assume the higher of the two figures, ie, 0.07A, we can say: 40Ah divided by 0.07A = 571.4 hours for the battery to go from fully charged to fully discharged if the car isn't used or kept on a trickle charger. That's just 23.7 days or 3.38 weeks. However, this is the theoretical maximum and you'll not see it in reality. Also, the battery will not be able to start the car long before it becomes fully discharged, so that will reduce the useable time as well.

I mostly agree with that but come on, owners have to take some responsibility because they are failing to do some research and failing to read the Owner's Manual. If anyone is buying brand new then they have months to prepare for its arrival. I was only buying a used car but from saying, "Yes, I'll have it" to actually picking it up, it spent a week at the dealership being prepped. I used that time to read the manual from cover to cover and was completely familiar with the car even before I owned it. Even before that, people should be considering if a hybrid car is even for them. There's a huge amount of difference between hybrid and conventional cars and they just are not suitable for some people and their driving style/driving habits. For instance, I wonder how many people realise (before buying the car) that if you run out of petrol then you'll need a minimum of 10-litres to be put in before even attempting to restart, and if you have three failed attempts the hybrid system can lock out and it needs to be transported on a flatbed (definitely not towed) to the dealership (or other hybrid specialist) to be reset? I wonder how many know that hybrids don't have starter motors or alternators before they buy the car? There are cars that do that but it's different technology. Lexus uses two 12V relays as a safety interlock. The 12V battery has to have enough power to operate the interlock in order to 'get access' to the hybrid system. Given that it's the hybrid system that charges the 12V battery by means of a DC/DC converter (takes the 288V from the traction battery and drops it to around 14.4V), it just can't happen. Not enough power to operate the interlock means no hybrid system, which means that it can't charge the 12V battery.

Not having a pop at you Elaine so please don't think that, but all this could have been avoided by simply reading and familiarising yourself with the Owner's Manual. If the dealership didn't supply one with the car then you can download one free of charge, from here https://www.lexus.co.uk/owners/about-my-lexus/manuals

Keep your money in your wallet because let's face it, none of them are much good are they? You don't want LFA on the plate because the car isn't an LFA and that would just look silly and needy, and the first one just makes no sense whatsoever - too much of a stretch to make it say Lexus.

Usually somewhere close to the item you're trying to troubleshoot.

This has all the hallmarks of a bad earth so unbolt it and clean up both the bolt itself, any washers, and also where it bolts into the body, with wire wool or emery paper so that the connection is clean and shiny.

Definitely the RX all day long. I'm on my third one now and absolutely love them, my current one being a 2018.

If you can't find the info you need I highly recommend buying a multimeter. As you can see here you don't need to spend a lot of money on one but they are invaluable for sorting out electrical problems. All you need do is to use the meter to find one fuse that is permanently 'live' and has 12V on it all the time. Then find a second fuse that is only live and only has 12V on it when the car is in ACC (or is it READY mode, I can't remember). Finally you'll need a good earthing/grounding point (any unpainted and clean screw/nut/bolt/bracket will do). It doesn't matter what the fuse you're tapping into is rated at because the 'piggy-back add-a-fuse' (one of these things) you'll use for the camera will have it's own fuse.

Mine was fitted by Lexus Preston about 3 weeks ago but they haven't got the geofence device yet.

According to this that I also posted on the 7th, the phone app is only for the more expensive S5 version of the tracker and not the S7 version we get:

This is the text that I posted in my topic "Did anyone else realise..." on the 7th September: Seems to be down to the battery as I've just found this text: The Battery Powered Retrieve has a 5-year life span from the date of installation. The battery is designed as a one-time use operation, therefore, if your vehicle is ever stolen, the Tracker unit will need to be replaced*

Ronnie, it's also worth a mention that as we recently found out, these trackers are a 'one-shot' device. If you're unlucky enough to have your car stolen then if (when) it's recovered it'll need a new tracker fitting. The unused portion of the three-year monitoring subscription can be transferred to the new one, but the question is - who pays for the new tracking device and its installation?

Well, I have to say that that's very unusual. Truthfully, I've never had any issues with Preston at all and I've been a very happy customer of theirs since the day it opened. I was in a couple of weeks ago and they were struggling with staff shortages and they were all running around like headless chickens but they coped very well and provided their usual high standards. I honestly don't know what to say to you Paul......

I find this situation to be really weird. I bought one of these Rewire Security DB2 trackers for just under 35 quid (price varies as offers come and go) and the sheer wealth of information you get from it is astounding, including the ability to set geofence zones as well as real-time tracking maps, journey history, distance and speed travelled and lots of other stuff. The only thing missing is the central monitoring and police involvement. My point is, with regard to both the phone app and the geofence device, if the DB2 can do it for less than £35 and with no hassle, why is the Lexus 'solution' seemingly so hit-and-miss and complicated?

I can't abide the factory nav in my 2018 RX so I prefer Waze, with Google Maps as a second choice. I think the way to do it in either of those is to change the volume while there's an announcement happening. May be worth a try?

Far better to call them on 01772 911394, choose the 'Servicing' option and then Option 2 so that the system thinks that the car is currently in the workshop. You then get to speak to a real human in the real service dept. Phil Partington seems to be the main man so ask if he's available and he'll get you sorted.

Complete guess, but I'd say that's logical and is probably what happens. When starting the car the first thing in the chain (or at least one of the first) is that there are two 12V relays that work together as a safety interlock. If the 12V battery doesn't have enough power to operate those then the hybrid system is inaccessible. Maybe the interlock is set up to somehow operate as above as well, although I don't know how they'd achieve that.