ColinBarber

🙂 I'm just making sure information is factually correct. Lexus in the UK do not recommend a service interval for sealed transmissions unless the vehicle falls into a severe maintenance category. Personally I'd go beyond what they recommend which I have stated previously, in the same way that I would recommend people periodically (every 1 or 2 years) re-grease their brake calliper sliding pins (if their vehicle has that type of brake design) to avoid them seizing. Lexus do not recommend this either but it is certainly worthwhile to avoid extra expense at some point.

Most Toyota transmissions won't go into top gear/overdrive until it is at a certain temperature.

Only for the severe conditions schedule when one of the following is met on a regular basis: Heavily loaded vehicle. (Example : Towing a trailer, using a camper, using a car top carrier, etc.) Extensive idling and / or low speed driving for a long distance such as police, professional / private use like taxi or door-to-door delivery use. Continuous high speed driving (80 % or more of maximum vehicle speed) for over 2 hours. There is no interval for the standard schedule which 90%+ of owners fall under.

I think it is just a specific load index, same situation with the previous tyres.

I don't think that is true at all. Most people in the US cannot believe we go 10k miles between oil changes, they are changing every 3 to 6k miles. They have experts in auto transmissions in every town, we just have a handful in the whole country. Oil analysis is quite common in the US, almost unheard of in the UK.

May just be the sound of the electric motor? Do you get the same noise going forward if you put it in EV mode?

In the US you have a choice of fuel grades but Lexus require the same octane rating here in the UK as in the US - you need to make sure you factor in the different rating system used between the two countries when comparing. However for the IS250 the type of fuel is irrelevant to carbon build up on the valves as the engine is only direct injection, no fuel ever comes into contact with them.

Good enough for a price, and able to supply in the quantities and locations required. They typically use a Japanese supplier for obvious reasons. When you get into the higher end then performance is put higher up the priority list and possibly the requirement for bespoke tyres (F series vehicles, LFA etc.).

Your problem almost certainly lies in the boot. Either camera, camera ECU or wiring in-between - likely moisture related. The camera puts out a composite NTSC signal into the camera ECU. This is converted to RGB, overlaid with graphics and the output sent to the screen. The wiring diagrams imply the Nav system output goes into the camera ECU then onto the screen via the same RGB cable, therefore if there is a problem with the camera ECU output or the screen you would be getting the same issue when displaying the nav screen.

Perform initialization of the power back door system (power back door ECU initialization) if one of the following is performed: The cable is disconnected from the negative (-) auxiliary battery terminal. Or the battery goes flat. A wire harness of the power back door system is disconnected and reconnected. The power back door ECU (back door motor unit) is replaced or removed and reinstalled. The ECU-B fuse is replaced or removed and reinstalled. If initialization is not performed, the power back door system will not operate. When the back door is open and the cable is disconnected and reconnected to the negative (-) auxiliary battery terminal, fully close the back door by hand to initialize the power back door system. Tech Tips Initialization is not necessary if the cable is disconnected and reconnected to the negative (-) auxiliary battery terminal while the back door is closed. The power back door ECU controls the locked or unlocked state of the back door based on its memory. If the power for the power back door ECU is disconnected and reconnected, the back door will need to be unlocked before it can be operated. If the power back door system does not operate and/or the back door does not open, disconnect the cable from the negative (-) auxiliary battery terminal. Then wait 10 seconds, reconnect the cable and perform initialization of the power back door system again.

I'd suggest that if you are at lights that the petrol engine has been turned off by the hybrid system, and you pull away under electrical power only. Then a second or two later the petrol engine starts and this is the judder. My initial thoughts would be a blocked EGR valve which can cause starting issues and probably at least semi-blocked on an engine which has done 220k miles. also check the engine mounts haven't worn/split which can cause engine shake when it starts.

The rear screens on the 400h are completely separate from the rest of the vehicle's Infotainment system. The latest design, which came out in 2008 and therefore would have been fitted to your 2009 model, have integrated DVD players in the screen unit. I don't believe they were available as a retrofit, wiring isn't in place to power them so wouldn't be an owner fit job in the eyes of Lexus. Knowing Lexus if they did offer them they would be outrageously expensive. IMO you are better off with iPads and holders. These old DVD units with the infrared headphones were never great. Certainly better than the older design pre-2008 but you can do much better in 2020.

No. Did you get your vehicle new?

So the shudder is coming from the petrol engine, and is running at the time and not trying to be started?

It will be more that 5 seconds. As soon as you connect the battery pack to the vehicle's 12v system it will be charging the vehicle's flat 12v battery and will very quickly pull down the voltage of AA batteries. By the time you have connected it up and turned on the ignition you may be too late. AA batteries aren't 2500mA, they have a capacity of 2500mAh. Manufactures don't normally specify the Amps they can provide but internal resistance of non-rechargeable batteries will limit it to just a few Amps. Eight cells connected to provide 12v are connected in series. Current is a constant through a series circuit. If one battery could provide 2.5A the whole battery will provide 2.5A, not 20A.

Can you confirm if the petrol engine is running when this happens?

What is the error code, there are multiple things that can light up the VSC warning?

Welcome to LOC 🙂

Have you replaced your radiator? Certainly worth doing at least every 10 years to minimum the risk of the transmission cooler failing and allowing coolant into the transmission, completely destroying the transmission. I see this as a bigger risk than the transmission fluid if you had to do just one - but obviously worth doing both. Certainly more transmission problems reported on these forums are due to a radiator failure than lack of maintenance on the ATF.

Has the hood actually popped? If not then a false alarm and dealers should be able to clear for around £60.

Sealing up the transmission was a way to stop the fluid absorbing moisture as it essentially becomes a sealed system - the pressure valves being filtered. Manufacturer thinking is that period fluid change actually increases water content/contamination into the fluid, especially as if you just to a pan drain and refill you are only replacing 1/4 of the total fluid. Toyota/Lexus do recommend replacement every 60k miles if you are on a heavy maintenance schedule (taxi, only ever short journeys) but never if on a standard schedule. Wear is minimal, good for 200k miles on the original fluid so whilst replacing fluid will reduce wear for most owners and vehicle lifetime it isn't a concern. Personally I'd probably replace at 100k miles if you intended to keep the vehicle for a number of years. For transmissions with a dipstick, maybe a pan drain/refill at 60k and then every 20k miles. Especially on something known to have issues, like the series I RX300.

I think you are going to suffer other issues long before you emissions go high due to carbon build up. Poor acceleration, poor starting, poor idle etc.

Not always, it has to be really bad for an error to be detected. I'd start with cleaning your MAF sensor as that is a simple thing to do.

have you ever had to change the O2 sensors? 99k miles and 13 years old, they might not be reading 100% which could result in higher than normal CO.

I've found the newer WLTP economy figures are much more realistic and easily achievable.