Yaris Hybrid 2020 TNGA - Hybrid System Malfunction

[YarisHybrid2016]

All mechanical and electronic devices are subject to the "bathtub" curve of reliability.

In the first weeks/months, probability of [a] failure is high, but the longer it performs to spec and does not fail, then generally the probability of failure reduces.

You then enter the period of long-term reliability, so long as things are maintained and not abused.

At the end-of-life, things wear out, and eventually fail if pushed too far. Probability of failure increases.

There are two kinds of outlier: operated perfectly but fails due to rare manufacturing defect, and; abused like hell, yet due to random variation it keeps on ticking.

[Nixy]

What damper are we talking about Teki? How did you treat the car harshly? 

[Teki Chan]

2 hours ago, Nixy said:

What damper are we talking about Teki? How did you treat the car harshly? 

The service explained that was like a clutch in a manual car. The message appeared when I stomped the gas pedal very harshly.

[Yugguy1970]

Back in the day I've kept driving when the accelerator cable snapped by using some string through the window.

Ive driven cross country with a failed alternator to a breakers to get a new one, knowing that if I got there without using any electrics I'd make it. Swapped it out a the breakers and drove home fine.

Can't do tbese kinds of things with most modern cars, let alone hybrids.  There will come a point in a hybrids age when it just won't work and you can't keep it going on a shoestring.

[Nixy]

Sorry but I feel that in an emergency U SHOULD definitely be able to squash the accelerator without a malfunction occurring with a damper or anything else.

[TonyHSD]

31 minutes ago, Nixy said:

Sorry but I feel that in an emergency U SHOULD definitely be able to squash the accelerator without a malfunction occurring with a damper or anything else.

And yes and no. 
Toyota hybrids has a clutch pack like manual transmission fitted between engine and MG1 and its the only thing that damper any violent vibrations between both power sources. There are two reasons for that: 

1. To protect the hybrid system components 

2. More comfortable drive , less vibrations and thuds

The reason why these cars goes into hybrid system malfunction failure is when the engine speed exceeds the speed limit  of the MG1 or when the torque of the engine goes above certain limits then a slip occurs and the system can detect that and cancel all power going into the driving axle. In most cases the car can safely continue after stop and restart. Toyota can and does issued a software updates about these “events “ and try to limit or stop this happening but in rare occasions it will happen. Most common time that this can occur is when you hit a pothole under heavy acceleration or when the on or more of the drive wheels loose grip again only under heavy acceleration, full throttle. 
Every time you smashed the pedal you can hear a thud when switching from ev to petrol, these is from the clutch pack and it’s damper springs which gets fully compressed, but when a this thud is greater than what the springs can take there is also a dry clutch friction plate that slipped and off set the synchronisation between engine and MG1 resulting hybrid system malfunction. It’s not only within Yaris cars but all hybrids with power split device. For some reason, Yaris gets a bit more of this thing happen, could be faulty parts, or not as high quality ones fitted. 
Engine misfire from bad fuel or egr problems can also cause clutch rattling and hybrid system malfunction. 
Here it is 

https://www.ebay.co.uk/itm/325285321825?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=BhRG1TTsSom&sssrc=2349624&ssuid=p34UK1z2T4m&var=&widget_ver=artemis&media=COPY

[TonyHSD]

Here a video to better understand what you have in your cars and how it works. 👍

 

[Cyker]

I do wonder if they undertorqued it or something; The Mk4 can deliver an incredible amount of instantaneous torque at almost all speeds when cruising (I use it frequently  ), and I wonder if they somehow miscalculated?

Ironically, when I got the hybrid malfunction it was AFTER I'd done a very high acceleration overtake; It happened when I lifted off!

I still haven't gotten it to do it again, despite occasionally trying to provoke it  

 

[YarisHybrid2016]

I'm finding this rather intriguing. Either gen. 4 delivers significantly more instantaneous torque, or the part isn't designed correctly...??

I've had times when driving my gen. 3 where I have been driving very aggressively over less than smooth roads, and the poor thing has been dragged screaming over holes and gaps in the pavement under hard acceleration. I've had wheel slip, TC activation, and sometimes, a loud THUD accompanied by momentary loss of power that feels like TC, but never have I had a hybrid system fault result, and the car picks up with no change on my part and carries on.

It's making me think that either Toyota are being over-protective of the system, and this message is more of an annoyance, or they under-spec'd the torque ring and it is slipping far more than it should.

The over-speed of the engine/MG1 components is concerning though.

I drive the Cross fairly aggressively (my wife hates it, and I do tone down my driving with her! 😄 ) but so far the Cross has been fine, even when experiencing wheel slip.

[TonyHSD]

2 hours ago, YarisHybrid2016 said:

I'm finding this rather intriguing. Either gen. 4 delivers significantly more instantaneous torque, or the part isn't designed correctly...??

I've had times when driving my gen. 3 where I have been driving very aggressively over less than smooth roads, and the poor thing has been dragged screaming over holes and gaps in the pavement under hard acceleration. I've had wheel slip, TC activation, and sometimes, a loud THUD accompanied by momentary loss of power that feels like TC, but never have I had a hybrid system fault result, and the car picks up with no change on my part and carries on.

It's making me think that either Toyota are being over-protective of the system, and this message is more of an annoyance, or they under-spec'd the torque ring and it is slipping far more than it should.

The over-speed of the engine/MG1 components is concerning though.

I drive the Cross fairly aggressively (my wife hates it, and I do tone down my driving with her! 😄 ) but so far the Cross has been fine, even when experiencing wheel slip.

You better take it easy as this usually happens at most inappropriate places and times like in a fast dual carriageway or motorway without hard shoulder during rush hour 🫢 and it’s not only annoying but also an ultra dangerous especially with todays driving standards with no safe distance between vehicles at all by most drivers and particularly lorry, buses vans and all trade in general. When happens you are loosing all power , car goes into N and you have only one option, to pull over if you can. 
 

[Nixy]

Hey the way this conversion goes I think this yaris mk4 car sounds outright dangerous. Maybe I should sell mine. I'd rather spend more fuel money on an ice car, than feel my life is in danger. 

[TonyHSD]

54 minutes ago, Nixy said:

Hey the way this conversion goes I think this yaris mk4 car sounds outright dangerous. Maybe I should sell mine. I'd rather spend more fuel money on an ice car, than feel my life is in danger. 

Not there yet.
It’s not the Yaris only that happens to, pretty much can be on any Toyota hybrids. With me was on Auris, with others on Prius etc. The truth  is that there is no guarantee this or similar will never happen to ice or full ev.
All cars has some limitations and once these are exceeded the obvious happens. No need to give up driving what you have because of something that may or may not happen. Same as you are going to sell the car because few members with the same model has had Battery problems. 👍

[YarisHybrid2016]

2 hours ago, TonyHSD said:

You better take it easy as this usually happens at most inappropriate places and times like in a fast dual carriageway or motorway without hard shoulder during rush hour 🫢 and it’s not only annoying but also an ultra dangerous especially with todays driving standards with no safe distance between vehicles at all by most drivers and particularly lorry, buses vans and all trade in general. When happens you are loosing all power , car goes into N and you have only one option, to pull over if you can. 
 

What speed are we talking about? From standstill? Hard accel from 20 MPH?

I have another test drive this week... maybe a good time to do some testing (on quiet roads, obviously).

[TonyHSD]

39 minutes ago, YarisHybrid2016 said:

What speed are we talking about? From standstill? Hard accel from 20 MPH?

I have another test drive this week... maybe a good time to do some testing (on quiet roads, obviously).

That’s about right 20mph. When happened to me I was at around 20mph and wanted more power to start climbing up a long step hill on fast dual carriageway. The car hit a deep pothole and the engine revved up  high for a fraction of the second and then all went quiet, there were few warnings and beeps on the dashboard, it was a total power lost the car went into N and started loosing speed quickly. I was lucky  there were no other vehicles immediately behind. After restarting the car it was drivable but all, warnings remained on the dash. I have a scan tool and run a diagnostic and reset the faults. Never happened again. . I also did checked the car transmission and no damage on visual inspection.

 
If you want to try on the test car, look for a deep pothole, something that can make the wheel loose contact with the road and just before that smash the accelerator to the bottom sharply as this is very important - fast and sharp press to the floor - the car response differently from usual acceleration and uses both engine and mg1 to push as much as it can especially when you have more change in the Battery. These are the events that needs to match to recreate my story. 👍

[Cyker]

One of the TSBs for the Mk4 reprograms the computer so it doesn't go into N - Mine had it, so when I had the warning the car's driving characteristics didn't even change, it just scared the smeg out of me with loads of needlessly alarming error messages  

It was quite funny as, after the initial shock, I started poking it and found I could still do a full-bore acceleration up to 70mph and it was absolutely fine (And after I pulled into a services to turn the car off and on again to get rid of the warnings (It cleared all except one), it actually performed better!!  ... but it turned out this was just because it reset the drive mode to Normal from Eco  )

I know people that had earlier cars (late 2020ish) lost all power when they had the slippy clutch malfunction, but none of the newer ones (2021 onward) or ones that have had the update will do that. (So don't ignore those recall notices!!  )

 

[YarisHybrid2016]

4 hours ago, TonyHSD said:

smash the accelerator to the bottom sharply as this is very important - fast and sharp press to the floor - the car response differently from usual acceleration and uses both engine and mg1 to push as much as it can especially when you have more change in the battery.

Interesting. Do you need to push through the button at the bottom, as well?

Maybe I've not seen this as I "roll" the throttle on, so not quick enough to trigger this function.

[YarisHybrid2016]

2 hours ago, Cyker said:

One of the TSBs for the Mk4 reprograms the computer so it doesn't go into N - Mine had it, so when I had the warning the car's driving characteristics didn't even change, it just scared the smeg out of me with loads of needlessly alarming error messages  

It was quite funny as, after the initial shock, I started poking it and found I could still do a full-bore acceleration up to 70mph and it was absolutely fine (And after I pulled into a services to turn the car off and on again to get rid of the warnings (It cleared all except one), it actually performed better!!  ... but it turned out this was just because it reset the drive mode to Normal from Eco  )

I know people that had earlier cars (late 2020ish) lost all power when they had the slippy clutch malfunction, but none of the newer ones (2021 onward) or ones that have had the update will do that. (So don't ignore those recall notices!!  )

 

That makes me wonder if this behavior is intentional, if they reprogrammed it to stay in D? Did it require maintenance action to clear the remaining message?

[Cyker]

I think it is; Going into full fail-safe mode is clearly overkill for a slight slip of the clutch plate and I think they recognised and addressed that.

I did have to take it to the dealer to clear the remaining message, although this was on a saturday and they just squeezed me in without checking it so I didn't get any codes.

[TonyHSD]

12 hours ago, YarisHybrid2016 said:

Interesting. Do you need to push through the button at the bottom, as well?

Maybe I've not seen this as I "roll" the throttle on, so not quick enough to trigger this function.

No, when you drive normally simply quick and sharp fully press the accelerator and the car should react immediately and try to provide full power available. And if you hit a pothole at that very moment, then you might be lucky ( unlucky) to see hybrid system malfunction.  
My car didn’t need anything else to be fixed, just scan the codes and delete. Never happened again although there where few similar situations, perhaps they were not as full power or wheel slip wasn’t as bad. 
It is indeed Toyota software that is trying to protect the system and my car had this tsb software update done few months before the incident. 👍

 

[Mikw]

I must admit my standard reaction when i see i'm about smash in to a  pothole is to stop acclerating, holding the steering wheel as tight as i can to stay in a straightline. I never accelerate when i see one coming.

I guess if i don't see a pothole and accelerate fully i could be in trouble.

The roads are so awful at the moment, it's like driving over a lunar landscape there's so many craters.

[Bernard Foy]

On 2/27/2023 at 3:12 AM, YarisHybrid2016 said:

All mechanical and electronic devices are subject to the "bathtub" curve of reliability.

In the first weeks/months, probability of [a] failure is high, but the longer it performs to spec and does not fail, then generally the probability of failure reduces.

You then enter the period of long-term reliability, so long as things are maintained and not abused.

At the end-of-life, things wear out, and eventually fail if pushed too far. Probability of failure increases.

There are two kinds of outlier: operated perfectly but fails due to rare manufacturing defect, and; abused like hell, yet due to random variation it keeps on ticking.

You’ve just given us the perfect definition of the human condition 👍

[Phil T]

Mikw said

“I must admit my standard reaction when i see i'm about smash in to a  pothole is to stop acclerating, holding the steering wheel as tight as i can to stay in a straightline. I never accelerate when i see one coming.
I guess if i don't see a pothole and accelerate fully i could be in trouble.

The roads are so awful at the moment, it's like driving over a lunar landscape there's so many craters.”

 

 

We used to drive on the left, now we drive on what’s left 😱

[YarisHybrid2016]

3 hours ago, Mikw said:

I must admit my standard reaction when i see i'm about smash in to a  pothole is to stop acclerating, holding the steering wheel as tight as i can to stay in a straightline. I never accelerate when i see one coming.

I guess if i don't see a pothole and accelerate fully i could be in trouble.

The roads are so awful at the moment, it's like driving over a lunar landscape there's so many craters.

There are a few sections of road I drive on where it looks flat, but the road work has sunk slightly so the whole width of the road feels like a pothole. I hate it.

I'm quite aggressive at avoiding holes in the road, but some roads became so bad I avoid them completely.

[TonyHSD]

That’s about right for the roads and what’s left of them 😂🫢

For the pothole, exactly the scenario, dark road no way you can see the road surface, fast roads you speed up , hit a pothole, out of the road with no power.
Toyota hybrids does not like that since the beginning. First 3 generation of hybrids doesn’t have a button to turn off TC up to 2013, and in event of both driving wheels loose grip the car simply stops, plenty of funny videos on you YouTube how Prius is strangling to climb up on a driveway because of that reason, and how to set the car in maintenance mode to disable traction control so be able to pull away from being stuck in snow. Later models can do everything until get the warning ⚠️ on the dashboard. 

[Will GX13]

Hiya.

Who would have thought.

Just happened to me on a local road, about 30mph, slightly up hill, loss of power was not noticeable, steering was fine, breaks definitely felt odd, as after 10 years with this car i got used to regenerative breaking assisting. Felt safe enough to continue to my destination, so took it easy and carried on for another 10miles. Parked, turned the car off, left it for few minutes, tried, all warnings asa per photo back on, except for traction control.

Car was always serviced at the main dealer, last service three months ago and hybrid health check done and passed. Waiting for main dealer to open the shop and will see if they can either advise what to do or take a look. 

Bit worried that main dealer may refuse to honour the 10 year warranty ( as car is over 100k now) and this is going to turn out v expensive. 

Anyone any ideas? I've skimmed through this forum, would be happy if this was something to do with 12v Battery. car is used daily, about 300 miles a week.

PS.

The only thing I've noticed recently, say few weeks, the transition between Battery traction and engine kicking in became noticeable- until that point it has always been silky smooth.