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Hi there! I am running into a snag. When I go into techstream, it keeps giving me a fatal error when I try and pull up the data list. Please see screenshot. Any ideas?

I did have a question on the gasket for the check overflow plug. Do you have a part number for it? I asked Lexus on eBay and they in turn supplied me a listing which is the exact same gasket as the one for the drain plug. Is it the same gasket? They don't seem to know and are asking me if it's correct, weirdly. Here's the listing they provided: https://www.ebay.co.uk/itm/255541251478?epid=1216787046&hash=item3b7f720d96:g:RBEAAOSwQ4dihNJH

Thanks, I'll have a go!

Not really as it's already hard to see because the bearing is hidden. I actually did press on the outer ring and it warped the bearing slightly as it no longer spun smoothly. So I ordered a fresh new one and fitted that, but this time pushed on the inner ring. My thinking is, it's the inner ring that's up against huge friction, so that should be made contact with and pushed along the shaft.

Hi @jumbodriveThanks a lot for your reply. I've just read your post, and wow, this is what I've been looking for - well done! Just off the top of my head... so, I should now fill in extra litre when the car is cold, then start car with techstream plugged in. Wait for temperature to increase to 30 degrees. Turn off car there and then, quickly get beneath, and drain out the excess from the check plug, then close it properly with a new gasket, then done. Correct? As for the bearing pullers - this took me ages to find, and I cycled through 3 pullers to find this one which worked very well: https://www.amazon.co.uk/Capacity-Bearing-Pullers-Puller-Separator/dp/B07T49N6NY/ref=sr_1_1_sspa?keywords=bearing+puller&qid=1661435573&sprefix=bearing+%2Caps%2C75&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzSE45RjFUOFY3RzFTJmVuY3J5cHRlZElkPUEwNTYzNDg1Mk4yRlo4Q0dGUlNaRSZlbmNyeXB0ZWRBZElkPUExMDA1Njc1MlhYRzdQVEw2Q1E5NiZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU= There will be a time where you will also have to use some nuts, when putting on the new bearings in order to ensure the bearing is pushed on with pressure applied to the INNER ring rather than the outer (which will warp it). I've attaching a pic to help understand:

Thanks for the reply. I'm keen to do it but am looking for a bit of guidance as I've heard that techstream is needed (which I have incidentally) but not sure how to use it and for what in this case.

It's just to adjust the intensity of the regenerative breaking. And, if you do upshift during acceleration, it revs sort of like an automatic as some sort of pointless simulation.

Good day. After having a check hybrid system error, with DTC code p2797-865, I honed in on the problem and that was that the bearings on the auxiliary transmission pump had siezed, so I changed them (as per Hayne's brilliant write-up on a different thread). Thankfully it fixed the problem and my hybrid system is now back. However, I've noticed 2 things that are a bit different this time. Firstly, there's a slight murming sound coming from the said pump when in operation. It's quiet but it is noticeable when I've got the windows all the way down and it's in EV mode. I don't mind it, but I do notice it. Secondly, the shifts from the low speed CVT to the high speed CVT (which happens around 65mph) have been fantastic and more rapid than ever, except the last couple of times just 4 days ago and yesterday where the car got stuck at 65mph for around 2 seconds before jerking up to the high speed CVT, allowing me to go faster. Very strange. At this point I think it's worth mentioning here, that a lot of the posts are quoting 5L as the rough requirement for ATF to refill the system. However, when I was doing the re-fill, after just 3L, it started to over-flow through the overflow check hole. I had kept the ATF bottles submerged in a water bath to keep them at roughly 35 degrees C before doing the re-fill. Once it was "full", I closed both the refill and the overflow check hole, and that was that. I've got 2 bottles unused (having only needed 3). I'm now half thinking, that because the pump and its hoses were empty, as soon as I started the car, some fluid level was now lost to the pump and that I should now repeat the fluid refill proceduce as a top-up move. I'm keen to know what others think. Also, could there be air in the system? If so, how would one bleed it? Another thing I noticed is, the central console from inside the cabin, in particular the heated/ventilated seats control panel, seems to be getting quite warm - not sure if this is related. I appreciate your time.

Hi everyone. Good news.. I successfully changed the bearings on my pump, both inner and outer, and I now have my hybrid system fully working again 😎. The guidance within this thread has been invaluable. However, I've noticed 2 things that are a bit different this time. Firstly, there's a slight murming sound coming from the pump when in operation. It's quiet but it is noticeable when I've got the windows all the way down and it's in EV mode. I don't mind it, but I do notice it. Secondly, the shifts from the low speed CVT to the high speed CV (which happens around 65mph) have been fantastic and more rapid than ever, except this one time just 2 days ago where the car got stuck at 65mph for around 2 seconds before jerking up to the high speed CVT, allowing me to go faster. Very strange. Has this happened to anyone here? At this point I think it's worth mentioning here, that a lot of the posts are quoting 5L as the rough requirement for ATF to refill the system. However, when I was doing the re-fill, after just 3L, it started to over-flow through the overflow check hole. I had kept the ATF bottles submerged in a water bath to get them to and keep them at roughly 35 degrees C before doing the re-fill. Once it was "full", I closed both the refill and the overflow check hole, and that was that. I've got 2 bottles unused. I'm now half thinking, that because the pump and its hoses were empty, as soon as I started the car, some fluid level was now lost to the pump and that I should now repeat the fluid refill proceduce as a top-up move. Did others do this? I'm very keen to hear from you, especially @Hayne (I hope you don't mind the tag!). Another thing I noticed is, the central console from inside the cabin, in particular the heated/ventilated seats control panel, seems to be getting quite warm - not sure if this is related. Thanks for reading!.

@Hayne Good day Hayne. Your write-up is very helpful but I'm having trouble finding the pump controller so I can disconnect the wiring. Can anyone help?

Hi John, I see you've got a 2007 gs450h. I've got the same car, 2006. Were you able to get confirmation from toyota/lexus if this is suitable for our car? I've been asking around but haven't got a firm yes. And I've checked the pictures of the bottles- they don't seem to say version A or B on them?

I appreciate your advice @Herbie thus far. I think the advice to check the 12V battery first should become an old adage. I will do just that in terms of fixes and will endevour to post updates here - perhaps someone may benefit. Something's telling me the pump may be at fault all along as for several months I've been getting lower than expected mpg, and I thought to blame the scam E10 fuel we now have to put up with... But my mate with the same car gets better mpg than me, so there's that.

Ah yes, that's a good point as there is no starter motor. Well I was able to drive yesterday but the central screen showed the battery as isolated. No engine charge coming in, no power going out to the wheels from the battery, and no regen coming in. Oddly, when these symptoms first ever happened, when I was on my way home, the regen was working then (but no engine charging battery or battery powering wheels.) And the drive last night did feel underpowered. However, weirdly, I could hear the high pitched whine of the electric motor (the same sound Prius's have). When I attempted to come back home however, the car failed to remain in Ready (just like when I had my previous knackered 12V battery), and this happened twice. I waited a few mins before trying again, and it was third time lucky and I was able to drive back home. Other strange symptoms I'm still having are; I can only control my driver window from my door (can't raise/lower other windows), memory seat settings seem to have been wiped, and my previously disabled seatbelt buzzer has been re-enabled. I shall have a go at resetting codes today and seeing what happens. [Please excuse the bold text... don't know why it's happening and it won't turn off].

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Hi all, I've just had a thought. What are the chances of several errors occurring due to a knackered 12V battery AND there being a genuine problem with the auxiliary transmission oil pump at the same time? Do you think I should just reset the fault codes using techstream at this stage? Given that I've replaced my 12V battery and the car actually does start and drive now (but without hybrid).

Also, on the tiny screen behind the steering wheel, Check VSC and Check ECB have now disappeared. Check (tire pressure) System also no longer shows, but Low Pressure (tire) does instead. So just the 2 errors cyclically.

Ah the wonders of Google. I decided to look up P0A0D and found that it is usually because the hybrid battery fuse hadn't been replaced correctly. I checked and indeed that was exactly the case! I sorted it and hey presto... the car now engine now starts! Check hybrid system is still there but what's different now is that engine remains running... which is unlike before I changed my 12V battery. The engine used to the just cut out after 5 seconds, or not fire up at all. So, a special thanks to @Herbie and others - you were right! So, why the engine running, I decided to run techstream again. The ABS/VSC/TRAC have all disappeared but a new code has appeared under the Hybrid Control heading, and that is: P2797-865 Auxiliary Transmission Oil Pump Driver (screenshot attached!). So, could this be the root of it all?

Ok good news. I've managed to do a techstream scan on my car and I have results to share along with screenshots. The main screen shot highlights problems in 6 areas, and I've listed these below along with the codes I found upon clicking further into them: 1) Hybrid Control P0A0D-350 High Voltage System Inter-Lock Circuit High (detailed screenshot attached) P0517-770 Battery Temperature Sensor Circuit High (detailed screenshot attached) 2) Engine and ECT No codes listed, but I've attached the screenshot anyway 3) Tire Pressure Monitor System C2121/2/3/4 Cannot Receive a Data from the Transmitter ID1/2/3/4 * Note that I had TPMS check system error from before this whole palava. 4) ABS/VSC/TRAC C1259 HV Control System Regenerative Malfunction C1310 HV System Malfunction 5) Air Conditioner B1421 Solar Sensor Circuit (Passenger Side) B1424 Solar Sensor Circuit (Driver Side) 6) Intuitive P/A B2243 Current Steering Angle Midpoint Unset These codes seem vastly different to the ones I got from the simple phone based OBD scanner I used before.

I mean from the central info display it shows when the engine is running and charging the battery .. when that's the case I never put it in N. But I do take your point going forward. On that note I have a question. If I put the car into P and it rolls slightly and then stops due to it being in P, is that bad for the car in any way? Or must I also apply the footbrake in conjunction?

Understood. I never do it when it's charging. When it's charging I keep it in D, or put it into P and apply footbrake.

That's very interesting... I'm hoping that the tpms will at least go once I get this main fault sorted.

Yes I'm working on getting techstream now... I've noticed one of the codes is to do with the oil pump of some kind. I looked around and apparently it's quite a common fault on my model of GS, which causes the same or similar symptoms. I'm thinking that I could jack up the car and get to it and open it and see if it has seized. Any thoughts on this? My car is due for a service anyway now that it's at 120000 miles (and I'd prefer to do it myself). And yes, I'm happy with the battery. I implemented Britprius's suggestion to get a larger one as I do tend to sit and listen to stuff for extended periods on ACC mode and it'd be nice to know I'll have charge left for longer.

8 ) Another symptom I forgot to mention is that my memory seat settings have been lost, and I can only open/close the driver window. This has been like this since before I disconnected any battery, i.e. as of step 4.

RECAP I thought it would be beneficial to just recap at this stage what's happened. 1) I was sat in my lovely lexus chatting to a friend for about half an hour. Car was fully on "Ready", with transmission in P... when the fateful errors starting showing in succession: i) Check Hybrid System ii) Check VSC iii) Check ECB iv) Check System (tire pressure) and then back to i). Of note is, I already had the Check System (tire pressure) from before for several weeks, so that's probably unrelated. 2) I drove home and noticed that the engine wouldn't charge my hybrid battery, but the regen charging worked fine (according to the central console screen). This might be an important point. I think I forgot to mention this first time. 3) On my way home, I arrived at a traffic light and so, to ease pressure off my foot, I put the transmission into N. I do this a lot without issue, and then shift back to D when lights go green. But, upon doing so, it wouldn't move. So I put hazard lights on, put into P, turned off car, on again, then P to D, then I was able to move. This happened twice. Thank God I was able to arrive home and reverse into driveway. 4) Several hours later, when I tried turning on, Ready would flash, engine would fire up, but only for about 5 seconds after which it would cut out and Ready would disappear. 5) I did an OBD2 scan using a bluetooth OBD2 reader linked to my phone, which yielded the following error codes: P2797 - Electromagnetic Oil Pump, P3191 - Engine Does not Start, P0A0F Engine Failed to Start, and C1241 Low or High Power Supply Voltage. 6) A day later, when I'd try turning it on, Ready wouldn't come on at all, not even flashing. I did a battery load test on my 12v, it failed the test, so I replaced it with a new Yuasa. Same error messages as before. 7) After breifly charging my new Yuasa off a wall socket (it reached above 13V), I fitted it in. I unplugged the main hybrid battery orange fuse, replugged it in after 10+ minutes. Tried starting again. Got the exact same result as point number 6 above. So that's where I'm at! I appreciate your continued guidance. Another point to note is: this car had a new hybrid battery fitted in 2018 by Lexus. The car is now more than 15 years old.

Okay... I've just fitted in a new 12v battery. And the problem persists. Car won't go into Ready mode. I even unplugged the main hybrid battery fuse for ten minutes.