2016 - complete power loss / breakdown

Hello everyone, been a lurker for a long time so about time I made a contribution. Unfortunately it’s not a positive one!

Bought a 4th gen 2016 in 2019. It had one previous owner, 23k miles on the clock after 3 years. Now has 101k after 6 years. Cost me £19500 from an approved used Toyota dealer. I have to be honest: I bought the car primarily for driving 35k work miles a year and I wanted bulletproof reliability. That’s why I bought Toyota and why I bought Prius. As I was spending close to £20k ($26k) I could have bought a better looking Mercedes/BMW but as my car is essential to my earning power I went for the ‘sensible option’. I’m starting to regret that now.

Firstly I’ve followed all recommended servicing. It had a full service in November at a Toyota main dealer. This morning I broke down after about an hour of routine driving. Car would not respond to my request for power via the throttle. I was on a main road in a town centre at the time and had enough momentum to pull to the side blocking traffic in one direction (UK roads are narrow!). All very embarrassing. The hybrid battery indicator displayed 1 bar for the first time ever (it’s never gone below 2 before), and the ICE was ‘spluttering’ -it remained on at all times but there was no response to flooring the accelerator nor any revving, no response to my input at all and it wasn’t recharging the hybrid battery. The display flashed up no warning lights and remained ‘READY’ even though there was no response in either D or R.

Now just as way of background about 5 days ago I (briefly) had similar power loss. Cruising in traffic in a 30mph zone. We were crawling and then needed to pick up speed -pushed the throttle but a very limited response like the car had gone into limp mode. Lasted about 15 seconds and then was fine. I looked under the bonnet after that: the coolant was on the low line whereas I remember back at Toyota in November they changed the fluids and it was at the full line. This concerned me and so I topped it up and kept an eye on it. But it wasn’t enough to stop the catastrophic failure this morning.

Anyway, after about 20 mins of waiting for a recovery truck the ICE started to sound normal and started to recharge the hybrid battery. 1 bar became 3. THEN I got power back and was able to drive to a safe location. I opened the bonnet and it was HOT -hotter than normal. The car drove home ok and is booked in for diagnostics at the dealer on Thursday.

Anyone an idea as to the problem? It certainly reminds me of this: T-SB-0241-17, “Reduced Power When Accelerating From a Stop,” but I hadn’t stopped and the coolant loss confuses me.

Sadly I’m disappointed in Toyota so far. The car had to be jump started 2 weeks after a full official Toyota service and the 12v battery replaced as ‘we don’t check the condition of the 12v battery during servicing’. I’ve also had to replace the front windscreen which is an infamous fault of the 2016 line.

I really don’t see any gain from having bought a Prius over any other car. As soon as the 100k warranty has been passed I get a breakdown, with loss of income and no doubt a serious repair bill. I’m also concerned there will be no codes showing when they hook up the diagnostic equipment and it will be a case of ‘well we can’t replicate it’.

 

When my windscreen splintered for zero obvious reason within a few months of ownership I searched for further information. IIRC 2016s were fitted with particularly lightweight glass to improve the fuel economy. 2017 onward better glass was used.

I can’t post links but a Google search will confirm.

 

Thanks and sorry to worry you. From all the evidence they are phenomenally reliable cars and the issues I’ve had seem to be ‘teething problems’ caused by buying the first year of a new model. You have a 2017 so the issues I’ve described should have been addressed.

 

Ok, an UPDATE for anyone following this.

I took it to a Toyota main dealer. They diagnosed what I guessed it was: ‘Reduced Power When Accelerating From a Stop (HV ECU)’. In the UK this is reference CP-00011T-TME. This happens after repeated driving on long downhill slopes and is pretty rare -(Cornwall where it occurred is rural and has numerous downhill slopes). Apparently a fault in the supplied firmware causes the hybrid battery to overheat and the car shuts down to protect the battery -(leaving me stranded for 20 minutes see the OP).

This is unique to certain Prius from the Tsutsumi plant manufactured before late December 2016 when the matter was resolved. My car has had the ECU flashed with the revised firmware.

The dealer attempted to charge me £250 ($330) for this as the car has just exceeded the 100,000 miles UK warranty. I refused and the charge was waived. Quite frankly I’m astonished that Toyota didn’t issue a recall for this but I'm back on the road and happy. I’m keeping an eye on the coolant level but was assured that some will have been burnt off as the car furiously tried to cool itself on the original firmware.

 

A further UPDATE. The car has driven fine since however the coolant is now again very close to the LOW line. 2 weeks ago it was filled right up to the HIGH line. Measurements taken when engine cold. There’s no sign of any leak. Hoses look fine. No out of the ordinary engine noises.

Should I be concerned about this? When I broke down the engine was HOT and the coolant was visibly bubbling. Appreciate any advice.
Thanks.

 

[FURTHER UPDATE]

More bad news unfortunately for those following this thread. The coolant continued to drop and so I took it back to the dealer -Vantage Toyota Preston. They have diagnosed coolant leaking into the exhaust system. You can watch a video of the technician here: https://filebin.net/w81tvtz0cz3wuv8f

To say I’m angry is an understatement. Despite being assured that a ‘Master Technician’ had dealt with the issue when it was brought in the first time that’s obviously not the case. Coolant was leaking *before* the breakdown and mentioned by me when it was brought in *after* the breakdown but they seemingly just did the firmware update, (which I as an amateur merely guessed might be the problem), and fired the car out the door as quickly as possible.

So I really don’t know the cause of the breakdown now. Was it the first TSB ‘Reduced Power When Accelerating From a Stop’ or was it the coolant leak which as I understand it is also a known failure ‘T-SB-0135-19 Low Coolant, MIL ON DTC P148F00, and/or Poor Heater Performance’ TSB: Coolant leakage at front exhaust pipe (Prius & Prius Prime) | PriusChat
(I’d appreciate it if anyone who understands cars could have a quick look at the video just to confirm that the technician is referring to that latter TSB).

Just to confirm that this is a car that was bought from an approved dealer, has had £1,000s spent on approved servicing and is used primarily for motorway/highway driving.

To add insult to injury the dealer has advised that whilst they are happy to consider the vehicle still in warranty for this matter, this particular repair is not included in the warranty (despite a TSB having been issued and the parts since upgraded by Toyota) and that a repair will cost £1750 ($2200).

I’m currently in the process of contacting Toyota (UK) HQ in Surrey and if needs be Toyota themselves in Japan to get this resolved. I guess we will see if they are as conscientious and concerned about reliability as they claim.

 

Yep, I’ve read the other threads about it. All the vehicles affected hit 100-110k miles and it fails. I’m an outlier -I was 99k when it happened!

 

Yes there is a TSB: https://static.nhtsa.gov/odi/tsbs/2019/MC-10166037-9999.pdf and that makes the situation even more unacceptable. In today’s world I would expect any car to do 100k miles without a serious fault arising requiring a £1750/$2200 fix. For it to happen on ‘the world’s most reliable car’ from the ‘world’s most reliable car manufacturer’ makes it doubly unacceptable. Frankly, it’s embarrassing.

If Toyota turn around to me and say “yes we acknowledge your car was built with a flawed critical part, yes we’ve replaced it on later cars as we know it’s faulty, and yes we’ve issued a TSB due to our concern about the issue” but you have to pay for the repair then there’s scope for legal action & media interest.

It’s a public holiday in the UK today but I’ll be pursuing it with HQ tomorrow. As it stands I’ve been shown the door with a bottle of coolant and a top of the range fully serviced Prius blowing white smoke out the back.