Is300h reliability

[Steve vialls]

Hi all

I am looking at purchasing an is300h, I drove one today which I found to be a nice pleasant drive and had good fuel economy too, I’m just wondering what the reliability is like on the hybrid system, I know the rest of the car would be good. Has anybody had any catastrophic expensive hybrid repairs?

cheers 👍

[ianhu]

4 years in Steve with my second hand is300h F sport. No issues with hybrid system or Battery yet. Touch wood. 

Cetainly the best car I have had. Would love something like rc-f but don't think I can justify it to myself. 

 

Ian

[Bounce75]

I done quite a lot of research before I bought my IS300h & it appears they are very reliable & the Hybrid system is tried & tested.

I am glad I made the switch as I am really enjoying mine.

[Steve_S]

Are "Steve's" more likely to buy IS300h's I wonder? 🙂

I have not had such a repair. For what it's worth my 2017 model has been the most reliable car I've ever owned. Only issue I have had is not appreciating how much more the 12V starter Battery drains compared to other cars I have had. More my fault for not reading the manual properly. 

If you look up the statistics the average cost to repair for Lexus is expensive but the reliability is good so those are the odds.

[Mikey B]

210K and nothing outside of servicing, a rain sensor (under warranty) and a bonnet catch.  Still on the original 12v Battery!

[colabora962]

Hi All,

           My 2015 IS300h is my first Lexus and I did do a lot of research before buying and I love it even after 2 years plus.

Only issues I have had is with the 12 volt AGM Battery that was nearing 6 years old.I know that it has lasted well and condensation on the inside of the rear windscreen drivers side, bottom corner, which I have added my comments in the post "water dripping into boot".

The hybrid system is guaranteed by Lexus for 5 years, under warranty, which you can extend by having a "Hybrid Health check " carried out annually for another 10 years if you wish at a Lexus Main Agent. The cost is circa £60 when I had it done in May this year and takes about an hour.

It  

           

[DBIZO]

On 10/16/2021 at 6:56 PM, Steve vialls said:

Hi all

I am looking at purchasing an is300h, I drove one today which I found to be a nice pleasant drive and had good fuel economy too, I’m just wondering what the reliability is like on the hybrid system, I know the rest of the car would be good. Has anybody had any catastrophic expensive hybrid repairs?

cheers 👍

If you keep it serviced at Lexus you get 12 month/10k-mile cover every time up to 10 years or 100k, after which you can still opt for extended warranty I think for extra dough. 

I'd join in with Colin and say the first thing I'd do is to swap the 12V starter Battery for a new one. If you're buying from a dealer, negotiate that into the price. If not, just buy a new one. You don't know what the previous owners did, how long the car's been left standing etc. These starters are smaller than usual 12V batteries, hence more susceptible to wear and deep discharge that lead to voltage drops when left standing for days. I learned it the hard way in an an airport carpark, at night. The erratic voltage levels must have messed up the computer and even roadside assistance struggled to boot the car up, after 30 minutes of charging both the dead Battery and the hybrid system (I had tried for a few hours using my portable jump starter Battery before they finally arrived). Don't be like me.

[Thackeray]

18 hours ago, DBIZO said:

(I had tried for a few hours using my portable jump starter battery before they finally arrived

Are you saying that you couldn't start the car with a portable jump starter? I have one in the glove box but I'm wondering if it might be pointless to bother with it.

[Mincey]

18 minutes ago, Thackeray said:

Are you saying that you couldn't start the car with a portable jump starter? I have one in the glove box but I'm wondering if it might be pointless to bother with it.

The portable jump starter always got me going again when my IS's 12v Battery was depleted. I think the longest I'd left it undriven was about 3 weeks.

[DBIZO]

10 hours ago, Thackeray said:

Are you saying that you couldn't start the car with a portable jump starter? I have one in the glove box but I'm wondering if it might be pointless to bother with it.

Yes, that's what happened. I thought I didn't know what I was doing, although "I came prepared": read the manual, had the fully charged jump-starter with high-capacity Battery (mine is like a small heavy suitcase, I keep in the boot, it's got a compressor too for slow punctures, which I also had after a few weeks, so no regrets buying), tried at the both the 12V and the front, at the engine. Well, I didn't, but then the man with the proper equipment arrived, and he couldn't really figure it out either. Erratic readings on the dashboard, no matter. After hours of trying, just when we gave up and wanted to call it a night and find a hotel nearby, the system just booted up, and then of course the engine started no problem. I'm none the wiser what to do any different next time. Probably call assistance after the first failed attempt not trying for an hour or two by myself.

It clearly had to do with the 12V Battery, because after an hour of driving, it only managed to boot the system on the Nth attempt, then after another hour of driving and an all night charging, it was back to normal. Got the Battery replaced, of course, after which leaving the car for 2 weeks at the airport is not a problem anymore. Tried it already (I was slightly anxious of course, human nature). 

Again, the only speculation I've got is that erratic voltages/currents from the 12V Battery screwed with the onboard computer. The Battery (I just bought the car second hand in April) was already old at about 6 years after manufacturing, and I also suspect it got damaged from ultradeep discharge sitting for months during the pandemic in a parking lot. A younger Battery with less abuse may not lead to the same drama, and your glovebox jumpstarter may be enough. 

What, of course, I don't really understand, is why the big boy batteries don't help the little one. Not in a hybrid, not in an EV. You have power in the car, just can't get it to the right place. There is probably a clear engineering reason for it, but maybe it's just that it doesn't make it past the cost-benefit test.

[wharfhouse]

In the past with non-hybrid cars I have found making the connection for the jump start and leaving it in place for a short while starts the dead car more reliably than trying to start it immediately. Maybe the same for hybrids - leave the jump start Battery connected for a while for things to stabilise and some power flowing into the dead Battery before pressing the Power button?

[Mincey]

1 hour ago, wharfhouse said:

In the past with non-hybrid cars I have found making the connection for the jump start and leaving it in place for a short while starts the dead car more reliably than trying to start it immediately. Maybe the same for hybrids - leave the jump start battery connected for a while for things to stabilise and some power flowing into the dead battery before pressing the Power button?

I'm sure I've seen this advice somewhere too - leave the jump start Battery connected for 30 mins then go for it.

[Ullager]

I purchased my 2014 is300H last year from Lexus Exeter with 31k on the clock. Only problems have been the rain sensor (replaced twice under warranty) & the rear camera, also replaced under warranty. I have only done about 3k miles due to lockdown but mpg seems to be about 45 with which I'm happy. I purchased a 3 year extended warranty & the first service I had done was for free. The next big one - due next year - will be expensive I believe at about £500. Overall, I'm very happy with the car but still hanker after another convertible. The is250 cabrios are getting a bit long in the tooth now.

[Thackeray]

5 hours ago, DBIZO said:

What, of course, I don't really understand, is why the big boy batteries don't help the little one. Not in a hybrid, not in an EV. You have power in the car, just can't get it to the right place. There is a probably a clear engineering reason for it, but probably it's just it doesn't make it past the cost-benefit test.

Many thanks for the detailed explanation. Much appreciated.

As for the high voltage Battery, my guess (based on no information at all) is that the top priority is to make sure the high voltage is completely safe and connected to absolutely nothing unless the car is operating correctly. I think I've read that there is an isolating switch on the high voltage Battery which is only turned on when the car reaches the Ready state.

If that's the case, it might be a challenge to design how to allow power from the high-voltage Battery to the 12v Battery in the event of some sort of fault (ie low voltage in the 12v battery). If the fault can't be safely identified it might not be a good idea to connect the high voltage. Perhaps there's a solution but the designers probably just assume that the 12v Battery should always be in good condition.

[200h]

you wont go far wrong buying the Is300h

as long as youre buying from a lexus dealership

with the service book fully stamped the car will be bullet proof,

remember the hybrid system dates back to the prius and has

evolved over the years so the system has been properly tried

and tested over the decades , ask a taxi driver why they've 

chosen a toyota / lexus hybrid they will give you the confidence

to make your purchase.

i'm on my 4th lexus hybrid and wouldnt have any other car now

i'm totally sold on the lexus brand.

[Scoops]

I did 80 odd thousand miles in 3 years and the only real issue I had with it was a failed wheel speed sensor which meant I couldn't use the cruise control and it showed an error. Replaced under warranty..

[DBIZO]

5 hours ago, Thackeray said:

Many thanks for the detailed explanation. Much appreciated.

As for the high voltage battery, my guess (based on no information at all) is that the top priority is to make sure the high voltage is completely safe and connected to absolutely nothing unless the car is operating correctly. I think I've read that there is an isolating switch on the high voltage battery which is only turned on when the car reaches the Ready state.

If that's the case, it might be a challenge to design how to allow power from the high-voltage battery to the 12v battery in the event of some sort of fault (ie low voltage in the 12v battery). If the fault can't be safely identified it might not be a good idea to connect the high voltage. Perhaps there's a solution but the designers probably just assume that the 12v battery should always be in good condition.

Good thinking, I suspect you're right, it must be about isolation between 12V and electrical 230/650V domains. Designing around such an isolation requirement  to get power from the NiMH Battery may be possible, but certainly not justifiable. Just maintain and replace the 12V Battery appropriately. I definitely will remember, don't fancy another late night rendezvous with AA in an airport carpark.

[ColinBarber]

21 hours ago, Thackeray said:

As for the high voltage battery, my guess (based on no information at all) is that the top priority is to make sure the high voltage is completely safe and connected to absolutely nothing unless the car is operating correctly. I think I've read that there is an isolating switch on the high voltage battery which is only turned on when the car reaches the Ready state.

 

Just seems to be the way Toyota has designed the system and they don't seem to want to change the design. Other hybrids and EVs periodically charge the 12v Battery from their traction Battery when the vehicle is parked until the traction Battery gets to a low state of charge itself.

[johnno]

I don't think you'll go wrong with a 300h. I traded mine in after 5.5 years and 50,000 miles and the depreciation was astonishing - I got £17,000 for a car that I paid £38,000 for new. The car was always a pleasure to drive and reliability was rock solid and - it only ever saw the garage for annual servicing. Mpg was an average of 45 over that time and the 12v Battery was still the original when I sold it. Can't think of any significant drawbacks. I was originally concerned about traction in snowy conditions as we live at the bottom of a long slope,  but it drove like a FWD car. Would have bought another but I needed a hatchback (bought a UX).