New XC40 sudden power loss - safety issue
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This is what happened on the night. Everything was 100% dead.
Before getting around to thinking of baling out, the first thing we did was to depress the hazard light switch, and they did operate. Then of course we tried to manually operate the start/stop button, and it then re-started the car.
We have read about hazard light operation, and appear to have had confirmed that hazard slights are designed to operate in such a situation, regardless of ignition status.
Before getting around to thinking of baling out, the first thing we did was to depress the hazard light switch, and they did operate. Then of course we tried to manually operate the start/stop button, and it then re-started the car.
We have read about hazard light operation, and appear to have had confirmed that hazard slights are designed to operate in such a situation, regardless of ignition status.
Your right about the 30 days, but within the first 6 months it assumed the fault existed from new, you don't have to prove it.Den48 wrote: ↑Thu Jan 02, 2025 11:01 am Hi
Are you sure about rejecting the car after 5 weeks? I understand that you can reject a car within 30 days , after this and for up to 6 months you can reject a car but you have to prove to the dealer that a fault (s) existed when the car was purchased/ taken delivery of the vehicle.
https://www.themotorombudsman.org/knowl ... ying-a-car
B4 AWD Inscription , Fusion Red, Blond interior. Drivers Assist, Climate, Tinted rear windows and Towing pack.
Ordered 14 Dec 20, delivered 10 March 21
Ordered 14 Dec 20, delivered 10 March 21
So glad that you did share, whilst having done what was required, as we need to know about these problems.berryberry wrote: ↑Thu Jan 02, 2025 11:13 am Thanks for your input. You are certainly right about the 'don't trust it' advice. While we are having ongoing discussions with the dealer and Volvo UK we thought it prudent to see what others think and we thought this forum was the right place for alternative viewpoints.
We came on to this forum as we noted that others do share problems and we feel that when you are taking on the might of a large organisation it's quite important to gain the backing of others when down in the trenches - thanks for your support.
2023 B4 Plus Dark FWD in Silver Dawn. Tinted Rear Windows. Spare Wheel & Tow Bar dealer fitted.
Gone - 2019 T4 R-Design FWD in Bursting Blue. Winter & Convenience Packs, Power Seat, Front Park Assist, Rear Camera, Spare Wheel & Tow Bar.
Gone - 2019 T4 R-Design FWD in Bursting Blue. Winter & Convenience Packs, Power Seat, Front Park Assist, Rear Camera, Spare Wheel & Tow Bar.
This is part of the problem of car dealers not explaining (or sometimes knowing about) what they are selling.berryberry wrote: ↑Thu Jan 02, 2025 10:58 pm Hi Neil
This theory of yours is gaining some considerable traction in our minds, as we researched further and got an answer to suggest that when power transfers from the 12v to the 48v battery, when we would have been nearing the junction for example, it can be that the 48v battery is responsible for providing the initial inertia to take off again, which it did, but then potentially spectacularly failed to transfer back to the 12v operation to proceed further as normal, hence the collapse.
This all seems quite plausible but we may (learning as we go here) be way off the mark. It does appear though that this appears to have happened to others in the past.
Any further thoughts welcomed.
So the car you have doesn't have a conventional automatic gearbox. What you have is a manual-style gearbox, with a clutch, but it is entirely controlled by a computer module to give the impression that it is a conventional automatic.
The effect of this is that when you're travelling at over 28mph (up to motorway speeds and beyond if you're abroad....), on your rev counter the little auto start/stop light will not have a cross through it, but just be a letter A with a circle. At that point, if you lift off your throttle pedal, the engine will switch off, the computer will move the gearbox into neutral and/or disengage the clutch, and as a result the car will just roll. Everything that on a conventional car (power steering, brakes, lights, even the water pump for the heater) that is normally powered by the "fan belt" on the engine is instead powered by the battery in the boot and so you continue to drive totally unaware that the engine has gone off. The moment you touch the throttle, the engine restarts and the car is back in gear faster than you could do it by hand.
When you come to a stop with the engine off, the motor under the bonnet (known as the "starter/generator" - as this is a mild hybrid the car cannot actually drive using this motor more than a few feet) which acts as both a charging unit for both batteries (the car also has a conventional 12v battery) turns both the engine AND gearbox to get you moving off from rest until the engine starts.
It sounds very much like when you put your foot down, the starter/generator motor moved the car from rest but the engine failed to restart, because for some reason everything died.
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Hi Neil
Feel that we may be getting ever closer to understanding which particular aspects may have been most likely responsible for what occurred. If you can bear with us a wee bit longer we really are appreciative of how your knowledge is coming to the fore.
You are right about dealerships pretty much handing over a set of keys and letting any driver, no matter how knowledgeable, drive away in relative blissful ignorance.
In trying to piece this together in a very condensed chronological order of events in the case of our incident, as we understand it, it would be like this:-
a) Heading along towards the junction at greater than 28mph the car is using the 12 v battery for its power.
b) Reducing the speed to less than 28mph has resulted in the car's engine being switched off and we roll along the last 100m or so. It is at this point that it's the 48v battery that has taken over
c) After having come to a stop, the throttle is depressed and the starter/generator kicks in and as is expected of it, allows the initial inertia to carry the car forward just a few feet
d) It should be at this stage that the 12v battery again takes over? ...yet it fails to do so. Is this correct?
e) Everything has died
f) The stop/start button is manually depressed and the car re-starts, and out of interest, which battery is now in use?
If we were to share this information with Volvo, we would still be asking them to check whether it was mechanical, electrical or software-related. At this stage we still suspect software, but either way we will not be taking this vehicle back, as our confidence is completely shot.
Apologies for the elementary understanding but we are learning, and either we are learning faster than the dealership or they are acting dumb.
If you can correct any further misunderstanding that we may have, this would be perfect.
Bearing in mind, without proper rectification this could happen again and of course has the potential to happen to someone else.
Meanwhile the fight behind the scenes goes on.....
Thank you for all your support.
Feel that we may be getting ever closer to understanding which particular aspects may have been most likely responsible for what occurred. If you can bear with us a wee bit longer we really are appreciative of how your knowledge is coming to the fore.
You are right about dealerships pretty much handing over a set of keys and letting any driver, no matter how knowledgeable, drive away in relative blissful ignorance.
In trying to piece this together in a very condensed chronological order of events in the case of our incident, as we understand it, it would be like this:-
a) Heading along towards the junction at greater than 28mph the car is using the 12 v battery for its power.
b) Reducing the speed to less than 28mph has resulted in the car's engine being switched off and we roll along the last 100m or so. It is at this point that it's the 48v battery that has taken over
c) After having come to a stop, the throttle is depressed and the starter/generator kicks in and as is expected of it, allows the initial inertia to carry the car forward just a few feet
d) It should be at this stage that the 12v battery again takes over? ...yet it fails to do so. Is this correct?
e) Everything has died
f) The stop/start button is manually depressed and the car re-starts, and out of interest, which battery is now in use?
If we were to share this information with Volvo, we would still be asking them to check whether it was mechanical, electrical or software-related. At this stage we still suspect software, but either way we will not be taking this vehicle back, as our confidence is completely shot.
Apologies for the elementary understanding but we are learning, and either we are learning faster than the dealership or they are acting dumb.
If you can correct any further misunderstanding that we may have, this would be perfect.
Bearing in mind, without proper rectification this could happen again and of course has the potential to happen to someone else.
Meanwhile the fight behind the scenes goes on.....
Thank you for all your support.
Your car stalled for some reason, be it mechanical, electrical, software or user error you won't find the answer on here. Indeed you probably never will. Good luck with rejecting the car.
XC40 MY24 B4 Ultimate Dark, Black Leather, Crystal White, 20" Rims
Lincolnshire England.
Lincolnshire England.
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Thanks for your good wishes.
The car didn't just stall - it completely died so we can dismiss user error on this occasion.
Although we don't yet know definitively what happened on the night in question, we do appear to be making some progress as to what may have happened, thanks to the expert knowledge that does exist on this forum.
The car didn't just stall - it completely died so we can dismiss user error on this occasion.
Although we don't yet know definitively what happened on the night in question, we do appear to be making some progress as to what may have happened, thanks to the expert knowledge that does exist on this forum.
Definitely not user error as you can't stall an auto, only the car can do that, and it sounds from what has been said so far that it didn't actually start!
Once the car has been rejected I hope that it is diagnosed and rectified and not just sold on. Are there regulations and processes for dealing with rejected cars? As with accident damage there should be a check on rejected cars.
Once the car has been rejected I hope that it is diagnosed and rectified and not just sold on. Are there regulations and processes for dealing with rejected cars? As with accident damage there should be a check on rejected cars.
2023 B4 Plus Dark FWD in Silver Dawn. Tinted Rear Windows. Spare Wheel & Tow Bar dealer fitted.
Gone - 2019 T4 R-Design FWD in Bursting Blue. Winter & Convenience Packs, Power Seat, Front Park Assist, Rear Camera, Spare Wheel & Tow Bar.
Gone - 2019 T4 R-Design FWD in Bursting Blue. Winter & Convenience Packs, Power Seat, Front Park Assist, Rear Camera, Spare Wheel & Tow Bar.
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- Posts: 25
- Joined: Mon Dec 30, 2024 7:04 pm
Thank you.
Fully agree with your point regarding rejected car processes. Have already raised this with the dealership but will reiterate this to Volvo.
Fully agree with your point regarding rejected car processes. Have already raised this with the dealership but will reiterate this to Volvo.