Losing faith with Check Hybrid message

[Ronock]

So i've owned my 2007 GS450h for about a year now, a few months ago I started getting a sudden barrage of lights and error messages and the hybrid system would  shut off; the car was still drivable but would only utilize the engine. 3 error messages would always appear, Check ECB, Check VSC and Check Hybrid Battery. Originally i stopped driving it all together until i got the code read and wiped, the code was P0A80 to replace the hybrid Battery. Once the code was wiped however the car drove totally normally, the Battery recharged as normal and was driving as good as new. However after driving it for any prolonged amount of time the issue would reappear along with all the lights and error messages, but i realized i could just disconnect the Battery and reconnect it when it happened and the car would lose all the saved errors and drive perfectly fine again; It was only while the error was on the dash that the hybrid system was turned off. So i wasn't in any urgent rush to fix it because it was only a mild inconvenience, over the next couple of months i tried a few fixes which included checking some fuses and getting a new 12V Battery. Nothing worked. So last week i took the entire Battery out of the car and reconditioned some parts of it, the connections between all the terminals were corroded so i cleaned all of them up, i checked all wires and connections which all seemed fine and all of the voltage's read within 0.05 of each other (All were at around 8). After reinstalling the Battery the car ran much better and i thought my issue would be fixed, however it took about 50 miles of driving and suddenly all the errors returned and i was back to disconnecting the Battery every 10/20 miles to reset the codes. Lexus said they can't diagnose the problem and simply said it would cost 4/5k to replace the Battery which is obviously lunacy because the entire system works fine, i just need to know what's triggering the codes to appear. Has anyone got any idea? it happens seemingly at random with only thing that increases consistency is amount of time driven but sometimes it would just happen again and again after only a few miles. Desperately looking for solutions now because any other professionals give me the same answer and i can't really afford to replace the whole system 

[Herbie]

Not having a pop but that amount of text in one block isn't easy to read and would have been better broken down into about 3 or 4 paragraphs

1 hour ago, Ronock said:

Lexus said they can't diagnose the problem

That's because you cleared the codes and have had things disconnected. You need to drive about 500 miles (doesn't have to be in one go but that's alright if you wanted to do that) for the system to stabilise itself and have any chance of giving you true readings. Trying to diagnose it now would produce odd results and lots of red herrings.

1 hour ago, Ronock said:

i checked all wires and connections which all seemed fine and all of the voltage's read within 0.05 of each other (All were at around 😎

How were you reading those voltages? A cell can show correct or normal voltage when you put the multimeter probes across it, but once you put a load on it that voltage can drop like a stone, so they have to be load-tested to show their true condition.

It may not even be anything to do with the Battery itself, but rather the Battery voltage sensor or its associated circuitry.

You have to be methodical and logical in your diagnostics and carry out tests both in the right order and using the right test gear. Have a look at the following link for a bit more information:

http://zatonevkredit(blocked word)/repair_manuals/raw_content/RM100000000X4NN.xml

EDIT:

I couldn't find anything for a 2007 GS450h, that link is really for cars from about 2012, so when it says The HV Battery is composed of 32 modules, and each module consists of six 1.2 V cells in series. The Battery voltage sensor monitors Battery block voltage at 16 locations. Each Battery block is composed of 2 modules in a set then this may not be correct for your car but the principles stand.

[Ronock]

1 hour ago, Herbie said:

That's because you cleared the codes and have had things disconnected. You need to drive about 500 miles (doesn't have to be in one go but that's alright if you wanted to do that) for the system to stabilise itself and have any chance of giving you true readings. Trying to diagnose it now would produce odd results and lots of red herrings.

The code was up when they scanned it, but what you are saying is for an accurate diagnostic i need to drive round with all the codes active until it can give a more accurate error?

Also yeah all the Voltage readings were just done with a multimeter but my assumption was a faulty cell would read different than the others regardless but i guess that's wrong

I'll be taking the whole hybrid unit out again soon, is there any way i can test the sensors or the circuitry while its out to eliminate them as possibilities? 

 

[Herbie]

1 hour ago, Ronock said:

The code was up when they scanned it, but what you are saying is for an accurate diagnostic i need to drive round with all the codes active until it can give a more accurate error?

Yes, that's right as I understand it. There have been a few posts on these forums from people saying that they've been told to come back for testing in 500 miles.

1 hour ago, Ronock said:

Also yeah all the Voltage readings were just done with a multimeter but my assumption was a faulty cell would read different than the others regardless but i guess that's wrong

Afraid so. As I said earlier a test can show the correct voltage when it's just stood there doing nothing but the moment you put some load on it and want it to do some work, the voltage can drop right down.

1 hour ago, Ronock said:

I'll be taking the whole hybrid unit out again soon, is there any way i can test the sensors or the circuitry while its out to eliminate them as possibilities? 

Not sure as I've never had to do it myself. All I can say is that the link I provided goes to a copy of the same workshop manual that Lexus techs use in the dealer workshops and as such, all the official test and diagnostic procedures are listed in there. For instance, if the DTC P0AFC-123 is also output, the chart tells you to go to 'Option B' and there's a 'Click Here' link to follow, which then shows you the next steps to diagnose the voltage sensor.

Good luck with it all mate.

[Ronock]

Thanks for the help, guess I've got a few more options to work through now and hopefully by the end it I'll have a better idea of what's happened

[200h]

hi

you could contact this company

https://www.hybridbatterysolutions.co.uk/

someone on here used them a few years ago and recommended them.

 

[Spacewagon52]

2 hours ago, 200h said:

hi

you could contact this company

https://www.hybridbatterysolutions.co.uk/

someone on here used them a few years ago and recommended them.

 

From previous posts, I would second that if you get nowhere yourself. They have a good reputation on here.

[Bluemarlin]

On 12/18/2022 at 8:38 PM, Herbie said:

Yes, that's right as I understand it. There have been a few posts on these forums from people saying that they've been told to come back for testing in 500 miles.

 

Yes, I was told to come back after 500 miles for a hybrid health check after the 12v Battery was replaced.

As a matter of interest, have you had a hybrid health check in the last 12 months, prior to this problem, and did it pass? If so then surely it will be covered.

[Ronock]

Sorry guys, just realized I never updated this post despite fixing it so for anyone who finds themselves in a similar situation.

I load tested each cell again as was recommended and actually found that all the cells dropped in their readings towards the 22nd cell in the row before that cell in particular fell to bellow 6 so it seemed like a bad cell that was effecting all the others. After buying a new cell online and replacing it all the issues went away, definitely beats the Lexus dealership £4000 offer to fix it. Another massive thanks to the people that replied in this chat

[Herbie]

Glad you got it sorted in the end Conor and thanks for letting us know what it was.

[Steven Lockey]

On 8/15/2023 at 2:33 PM, Ronock said:

Sorry guys, just realized I never updated this post despite fixing it so for anyone who finds themselves in a similar situation.

I load tested each cell again as was recommended and actually found that all the cells dropped in their readings towards the 22nd cell in the row before that cell in particular fell to bellow 6 so it seemed like a bad cell that was effecting all the others. After buying a new cell online and replacing it all the issues went away, definitely beats the Lexus dealership £4000 offer to fix it. Another massive thanks to the people that replied in this chat

Was going to say, thats exactly what happens with bad cells 😉

It flags the error and keeps flagging it till you clear the code. At which point it waits for the cell to play up again before it flags it again. 
Often the cells only fail under larger loads so after clearing the codes, it a while before the cell actually does something funny.

Had exactly the same issue. 

As the cell gets worse, the computer will react more harshly. When the cell is failing completely or overheating, the computer will
fully shut off the engine as well (aka ready light goes off) if it thinks it might be dangerous. Normally this only happens if you've
been ignoring the warning message for a long while 🙂