GS450H Hybrid battery dying - Car cuts out while driving

[Steven Lockey]

Hi all

Scenario:
   I just purchased a GS 450H with a lot of miles on it (177k) and surprise, surprise
the hybrid Battery was dying.

Well, I got some cash back from the dealer and have a new hybrid Battery on order
to be fitted. 

The issue is, when I'm driving the car will sometimes cut out, all the electronics e.t.c.
are still operating fine, no interruption on music or lights or anything, but the ready
light will go out and pressing the accelerator at this point does absolutely nothing. I
believe it does beep at me as well. Everything else seems absolutely fine.

If I pull over and put it in Park, the engine restarts instantly and without any issues
and I can drive off without any problems. It does sometimes seem to 'drag' when
I pull off, I can see its trying to recharge the Battery at this point on the info screens.

Using my OBD reader, the only issues on it are with the hybrid Battery.

I need to drive my car to get the new Battery fitted (or pay for an expensive tow) but
its pretty scary when the engine cuts out when you are on the motorway! And I
really don't want this to happen when I'm going round the M25! 

Questions:

1> From what I've read, this problem is basically that the system tries to draw power
from the Battery, as its on it's way out it doesn't get as much power is it expects and
throws a wobbly. Does this seem right?

2> Is there any way to reduce how much power the hybrid motors try to draw to reduce/
eliminate this or even tell the system to just run on the petrol engine? 

3> Is there any way to restart the engine without having to stop the car? If I didn't have to
come to a full stop when this happened like in a normal (read old 😉 ) type of car
then I could at least get there in relative safety.

Any other advice would be greatly appreciated.

Thanks 

Steven Lockey

[Herbie]

I can see this being a very expensive job one way or the other - so much so that I'd be returning the car to the dealer as not fit for purpose and get my money back.

I'm no expert by any means but in my humble opinion the failing traction Battery is more than likely not the cause but a symptom - what's making it fail and will it make the new one fail too?

As long as the hybrid health check is carried out annually, Lexus extend the warranty on the Battery each year to a maximum of 15 years and as far as I'm aware there's no mileage limit on that.

Hybrids don't have a traditional starter motor (I believe it's MG1 that starts the petrol engine) or alternator. In fact, anything that would normally be driven by a belt from the engine, such as power steering pump, aircon compressor etc., is done electrically on a hybrid and controlled by the hybrid system. When that READY light goes out and the hybrid system fails, you lose all these things and the car cannot be driven on the petrol engine alone.

[Hangie]

It doesn't look like a Battery problem. If Battery would be too weak you just get error message and continue on petrol only.

I would put my bet on transmission (where whole hybrid tech is), or maybe something like inverter which force the car into that state.

As Herbie mentioned Lexus hybrid warranty is for up to 15 years so if you got that I would go to Lexus. If you don't have that it might be too late for that car as value is low and any repair will be uneconomical = car for spares.

Finally 177k miles is not that much, it is more probably lack of proper maintenance - for example when was the transmission oil changed last time ?

[Farqui]

Hi Steven, welcome to the forum.

You mention that the dealer provided a discount on the Battery, so was this for the main traction Battery? 

If the fault was known at purchase then you will have less rights to return the vehicle to them for repair at their cost.

Was the vehicle purchased from a Lexus dealer?

You say the vehicle cuts out at motorway speeds but does it drive okay at lower speeds? 

If so, then that answers your question of how to reduce the demand on the systems...don't press the throttle so much ;)

Do you have or are you lined up to get a full diagnostic done?

Good luck getting it sorted and keep us posted on your progress.

[Steven Lockey]

Hi,
  Thanks for the replies

The dealer sold it as good but turned out the hybrid Battery is having issues. This is the main hybrid Battery
yes, not the 12v Battery. The dealer agreed to refund me equal to the cost of getting the Battery repaired
from quotes I had, but I figured I'd be best putting that money to a new Battery instead.

It wasn't a lexus dealership no. I don't think there is warranty on the car but I'll check that when I get home.
I had thought it was only a 10 year warranty on the hybrid Battery and that is 12 years old now.

The car can cut out at any speed, it seems to only happen when I come off of the accelerator. If I have my
foot on the accelerator so the petrol engine is providing power then it doesn't seem to cut out at all suggesting
that the petrol engine is fine. It's never cut out when going up-hill for example, its always when I take
my foot off the accelerator it seems. Sometimes it will be fine for an hour, other times it will cut out every 5 minutes.

I've seen people on this forum saying they had the same issue and replacing the Battery solved it completely.

If there was a problem with the inverter, wouldn't it show that on the error codes on the OBD reader? I've experimented
with it quite a bit including clearing the codes and its always the Battery codes that appear on the same
modules of the hybrid Battery been faulty which would suggest to me its the Battery itself as if it was an
inverter problem it would be random which cells it was complaining about? Also wouldn't it be showing inverter error codes?
The codes I'm seeing are Battery module failures (5 of), Replace Hybrid Battery Pack and Hybrid Battery pack deterioration.

I'll check when the other bits were done on the service history. If its was a transmission failure however, wouldn't this produce
an error code? I would be expecting if it was anything other than the Battery which is already showing error codes
then I would be expecting to see some sort of error on the OBD reader?

The car seems to run perfectly smoothly until this occurs, absolutely no issues starting the car or moving off, no knocking
or other symptoms which would indicate any transmission problem.

Thanks

Steven Lockey

 

[Hangie]

Battery warranty was extended to 15 years some time ago, so your car is still eligible if yearly service is done.

I have never heard about batteries issues with such symptoms as yours hence I'm betting on another components of hybrid drive.

Are you checking with a proper Toyota interface and tech stream software ? Have you tired to check the car status with tech stream when "ready" light is off but ignition is on ?

Maybe controllers are faulty and don't store error, or maybe your problem is so rare there is no error code for that - for example gearbox ECU is handing up or similar. 

[Steven Lockey]

Its possible but I think that would be very unlikely. Even if there was an unknown error I would expect the car to produce an error code if it was the generic 'something went wrong' code.

I'd be very surprised if it was an inverter issue since when the car is working it accelerates perfectly(hybrid and petrol) and I can see the regenerative breaking is also functioning fine. The hybrid kicks in when accelerating normally. From what I understand if there were issues with the other parts of the hybrid system I should be seeing other error codes been produced. 
Also if it was an inverter issue I would expect the issue to happen more when the inverter is under strain than anything else but I can quite happily put my foot down and the hybrid system functions perfectly. I can also see it regenerating power at it's maximum listed rate under heavy breaking.

Given a few people have said this issue can be caused by the Battery, I'm kinda betting on that. 

I've only looked up the error code on my OBD reader so far and cross-referenced that with Lexus. I've downloaded techstream and have ordered a OBD to USB cable but until that arrives can't do much more.
 

[Steven Lockey]

Does anyone know where I can find any information on this 15 year warranty?

I've got a load of paperwork that came with the car at home so I think it has had a yearly service.

I've not seen this before, I thought as the car was 12 years old it would be well out of warranty! 
More so with 178k on the clock!.

If it is in warranty that would make me a very happy bunny!

Thanks

[Farqui]

The 15 year warranty relies on the vehicle having a hybrid health check in the last 12 months / 10k miles.

This is independent on servicing.

Info here, see the Warranty sub section; https://www.lexus.co.uk/owners/servicing-and-maintenance/hybrid-health-check/#health-check

[Steven Lockey]

Many thanks Farqui, 
  I'll have a look to see if the previous owner did the hybrid health checks on this car.

I'm guessing he didn't but I can but hope!

[Farqui]

Fingers crossed eh

[Hangie]

When I bough my previous GS I haven't received usual certificate for the "hybrid health check", but it was serviced by a dealership according to the service book.

What I have done is just gave them a call and after a week they has send me over duplicate 🙂 So if you have a dealer stamp give them a call.

[Lwerewolf]

Only when you ease off the throttle... try driving in "sports" gear mode (S-mode, next to D), this keeps the engine on. When the engine switches off, the auxiliary oil pump in the transmission runs to maintain oil pressure for the MG2 2speed auto. If you're clearing the codes via a reader (which you shouldn't do - the state it's in when these codes are set protects the Battery to an extent), it might be this... if the HV Battery codes are present, the engine always runs, the info screen shows no power flow and regen braking is disabled, amongst other things.

In other words, might be a failing pump.

[Steven Lockey]

Thanks Lwerewolf, but I don't think this is the case here.

I believe you should see an error code if this is the case (p2797) which I don't get. 

Also from what I've read, if this happens, the car drives normally on the petrol engine but just refuses
to use the hybrid system.

In my case, when the car is working, everything seems to function perfectly
including the hybrid system which run normally both accelerating using the hybrid and the regenerative
braking.

I'd be very surprised if there was an error with the pump but it wasn't putting out a error code
for it as from what I understand it would output that code as soon as it saw the transmission oil pressure
been too low.

@Farqui
Yep, I can't see any other faults at all other than the Battery and I've done every test I can 
think of sort of taking it an actual engineer. So guess I'm going to have to cross my fingers and
hope I'm not about to waste a load of cash! 

I'm generally quite good at working out where the problem lies with the car, I'm just absolutely terrible
at fixing it! 🤣 Really hoping it is just the Battery as everything else I try to test seems to come up good!

Knowing my luck, I'll spend thousands trying to fix it and it will turn out to be a loose wire somewhere!

[Steven Lockey]

Oh and I did try driving it in 'S' mode and it did the same thing so not that. 

I did think it might be the Battery overheating as the Battery fans do run like crazy all the time. Maybe the air-vents
are a bit blocked and combined with the Battery been on the way out this is causing it to overheat?

Would Battery overheating cause a error code and the car to shut down? This would make sense as
a fire prevention measure, but I would have expected a different error code to show up if there was
an overheat problem.... but I can't see one listed for it so it might just display the Battery error code on an overheat.

[Hangie]

Main issue with a Battery theory is when anything "bad" is happening with battery hybrid system is shut and car should run on petrol engine only. Battery would only be needed to start the engine.

It is not the case for you which makes is most peculiar issue. What is also important here why when you go to "P" engine is suddenly starting ? That would mean something is actively blocking it when it is not in P.

[Steven Lockey]

@Hangie I thought that at first as well, but reading around it seems that the Lexus will keep trying to use the hybrid
Battery unless it thinks it is totally dead. If it just thinks a few cells in the pack are dead, it will throw up loads of warnings
but the car will still function normally, including continuing to try and use the Battery pack.

When I said 'instantly starting' I was meaning when I put it into P, pressed the brake and hit the power button again.
Not that it instantly started the engine as soon as I moved the shifter. Apologises, I should have been more clear.

If it was a transmission pump issue it should be showing an error and should automatically shift to petrol only mode
which doesn't seem to be happening so I don't think this is the cause. Also from what I've read as soon as this
error is detected, it puts the car into some limited mode.

If it was an inverter issue, well, I actually used to work as an electronic engineer and this would be one very strange
inverter issue! Also this should also output a specific error code which isn't been produced. 

This is why I was thinking its a Battery error as the old cells can sometimes produce a unreliable current which can spike
and drop and I was thinking that might be the issue. These issues often appear intermittently (just like mine) and
tend to temporarily resolve themselves (just like mine).

They can also overheat badly when you attempt to charge them, my other thought was as I was letting off the gas,
the power was been switch to charge the hybrid Battery, causing a temperature spike, and the computer sees this
and shuts the car down to prevent a possible fire? 

Hmm, just read elsewhere that a Battery overheat will cause the car to shut off entirely like mine is doing and is also
producing no error codes other than the normal Battery failures. It looks like we may have a winner!

It makes a certain amount of sense because if its a single cell that is overheating, then by the time I've pulled over
to restart the car, it's cooled down sufficiently for it to not moan again. Seems most of the other hybrid systems
on the car will flag a specific code if they are overheating but the Battery doesn't. 

If anyone know any different, please let me know! 🤞 this is the issue and the new Battery will sort it!

On that note however, does anyone know an easy way to clean the hybrid Battery fans? I took a look at the fans
on the behind the back seats and they are quite dusty but I couldn't see any easy way to get the covers off for
access.

[Lwerewolf]

1 hour ago, Steven Lockey said:

@Hangie I thought that at first as well, but reading around it seems that the Lexus will keep trying to use the hybrid
battery unless it thinks it is totally dead. If it just thinks a few cells in the pack are dead, it will throw up loads of warnings
but the car will still function normally, including continuing to try and use the battery pack.

No.

Battery codes = hybrid system failsafe/limp/etc - no torque fill, engine always on, "sluggish" (there's still a lot of power in the GS, the delivery is severely delayed though), info screen shows no power flow.

There's a "hybrid system overheat" message that the car can display.

What are the exact codes?

Re: the pump  - I recall reading instances in several places where the pump was causing issues without throwing codes.

Re: Battery fan - there's only one, you can access it by removing the top/center trim in the trunk... well, that and several pieces of plastic ducting. I haven't removed the filter itself yet.

[Lager shandy]

Why haven't you phoned lexus to ask about has my car got a Battery warranty via your reg number and why haven't you popped the car in for a hybrid health check ,this will load test your system and give you your answers .You sound like your a mechanic trying to sort an issue maybe for your garage or customer .you talk a lot but are not saying you have had anything correctly tested just that the Battery is going to be fixed and that will sort this with rose tinted glasses .you say your experienced but carn't work out how to unbolt a back seat assembly to clean out some fans . I'm sorry to sound a bit harsh but your not listening to the advice given 

so let's start again

1) how long have you had the car since you paid the slimey salesman if within 30 days take the car back .

2) has it got lexus history 

3) have you phoned lexus to see if your hybrid checks have been carried out .even if not have one done to prove issue with car if taking back to dealer 

4)Who is going to fix or replace your Battery and how much have you been quoted .

 

[Steven Lockey]

The hybrid system overheat code is for the hybrid engine not the Battery.

My engine is not always on, its still using the hybrid system for acceleration and regenerative breaking.

I've not got the code numbers to hand but the codes were for:
1> Replace Hybrid Battery
2> Hybrid Battery deterioration
3> Hybrid Battery module low voltage. (up to 5 of these)

I've checked all the codes with Lexus and they are all Battery only issues. None of them relate to any other
part of the hybrid system.

[OldTrout]

3 hours ago, Steven Lockey said:

I did think it might be the battery overheating as the battery fans do run like crazy all the time. Maybe the air-vents
are a bit blocked and combined with the battery been on the way out this is causing it to overheat?

The vents can get restricted - having a dog in the car doesn't help. I don't think I have ever heard my fans. It is straightforward though tedious to remove the boot trim and then remove the duct connecting the fan to the vent on rear parcel shelf. It is then easy to clean.

John

[Steven Lockey]

Quote

Why haven't you phoned lexus to ask about has my car got a battery warranty via your reg number

Cos I had never heard of the warranty going over 100k miles before and was only informed about it
what two hours ago while I was at work.......  Am also fairly sure the previous owner didn't have the health
checks done but might be wrong so I will check.
 

6 minutes ago, Lager shandy said:

why haven't you popped the car in for a hybrid health check

This is something I am thinking of doing, but having looked into it they don't actually do
much you can't do yourself with an OBD to USB cable and the free software from Lexus.
The load test is the main thing and I already know it will fail that as the Battery is clearly on the
way out anyway. I'm not a mechanic but I was an electronic engineer so I've got a pretty good
idea about how electronics work!

14 minutes ago, Lager shandy said:

You sound like your a mechanic trying to sort an issue maybe for your garage or customer .you talk a lot but are not saying you have had anything correctly tested just that the battery is going to be fixed and that will sort this with rose tinted glasses .

I wish I was a mechanic! 
And define 'tested'. Most of the 'tests' done other than on the Battery are just reading the sensor codes. 
The reason I am asking is to see if there are any other likely problems that might be causing the car to shut down like this that aren't Battery related but so far all the things 
people have suggested, well it would be very surprising if they were the cause of the issue. The thing is, this car has so many sensors, the common errors should all
generate error codes. 

Am I very much hoping its the Battery, yes 100%. 
Am I saying that is the only possibility.... no of course not otherwise why would I be posting here asking about it!

21 minutes ago, Lager shandy said:

you say your experienced but carn't work out how to unbolt a back seat assembly to clean out some fans . I'm sorry to sound a bit harsh but your not listening to the advice given

Please don't misrepresent me.
1> I didn't claim to be experienced at any point
2> Where did that come from? I don't have X-ray vision to work out what bolts are connected to what through the seats do I?
I am more than capable of unscrewing them, I just asked if there was an easy way to get to them as I've not been able to find
a decent guide to removing them and don't want to accidentally unscrew the wrong thing...... Its called been careful as the
last thing I want to do is cause more problems. 
3> How am I not listening? People have made suggestions and I replied with my it doesn't match what I'm seeing. I haven't
at any point said this isn't the problem, I've just said it doesn't match what normally happens in this scenario based on what
other people on this forum have said when describing their problems..... There have been many good suggestions that I'm 
very appreciative that people made, but that doesn't meant they are right.....


 

[Steven Lockey]

5 minutes ago, OldTrout said:

The vents can get restricted - having a dog in the car doesn't help. I don't think I have ever heard my fans. It is straightforward though tedious to remove the boot trim and then remove the duct connecting the fan to the vent on rear parcel shelf. It is then easy to clean.

John

Thats really useful, I wasn't sure if you needed to go via the back seat or the shelf in the GS450h, I've
not been able to find a decent guide for cleaning it anywhere.

I guess to clean the actual parcel shelf bit itself you've basically got to remove the whole array from the top of the Battery?

I can hear my fans going like crazy whenever this happens, even when the engine is running.

[OldTrout]

 

36 minutes ago, Lager shandy said:

You say your experienced but carn't work out how to unbolt a back seat assembly to clean out some fans

It's a GS. The Battery cooling duct is accessed from the boot,

 

[OldTrout]

Steven,

I should have said a call to Richard at Hybrid Battery Solutions in Northampton may save a lot of hassle. He is very experienced and has an excellent reputation on these forums. He is also a member I think. Richard?

John