New XC40 sudden power loss - safety issue

Faults and Technical chat for the Volvo XC40
berryberry
Posts: 25
Joined: Mon Dec 30, 2024 7:04 pm

Post by berryberry »

For those who took an interest in this case.....

It was 4 weeks today that the incident occurred, and Volvo still have our car, and the dealership have been liaising with Volvo Technical UK during this period.

Today we received an update that they are now asking the dealership to check the wiring and readout codes of the BCM (Brake Control Module) and ISGM (Integrated Starter Generator Module), as their most recent report notices that there is a code suggesting poor communications between these units.

They are now checking 12v battery voltage, connections and wirings around these items, and further readings from the ISGM unit.

Thanks to those on this forum who pointed us in the right direction, we were able to become actively involved in pursuing possible theories and we do appear to have amassed considerable traction, unlike the car on the night, which caused us significant trauma.

As this represents a significant safety issue we will keep those posted with the final outcome.

ChrisLF
Posts: 1870
Joined: Wed Apr 24, 2019 8:21 am
Location: Heart of England

Post by ChrisLF »

Good to hear that they are taking your experience seriously and investigating it in detail.
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.
GKSmith
Posts: 86
Joined: Sat Feb 10, 2024 10:50 am

Post by GKSmith »

berryberry wrote: Tue Jan 14, 2025 8:29 pm For those who took an interest in this case.....

It was 4 weeks today that the incident occurred, and Volvo still have our car, and the dealership have been liaising with Volvo Technical UK during this period.

Today we received an update that they are now asking the dealership to check the wiring and readout codes of the BCM (Brake Control Module) and ISGM (Integrated Starter Generator Module), as their most recent report notices that there is a code suggesting poor communications between these units.

They are now checking 12v battery voltage, connections and wirings around these items, and further readings from the ISGM unit.

Thanks to those on this forum who pointed us in the right direction, we were able to become actively involved in pursuing possible theories and we do appear to have amassed considerable traction, unlike the car on the night, which caused us significant trauma.

As this represents a significant safety issue we will keep those posted with the final outcome.
Good to know that it's under investigation. Hope things turn out well for you.
Thanks
Gavin
Volvo MY25 XC40 B3 Plus Onyx Black
Stovo
Posts: 290
Joined: Thu Sep 14, 2023 2:41 pm

Post by Stovo »

You still going through the rejection process? If so, what has been their response?
2024 C40 Single Motor RWD Plus.
Felindre
Posts: 902
Joined: Wed Dec 23, 2020 2:19 pm
Location: South Wales, UK

Post by Felindre »

BCM usually refers to the Body Control Module, the main controller for the car. The brakes controller is usually referred to as ABS.
B4 AWD Inscription , Fusion Red, Blond interior. Drivers Assist, Climate, Tinted rear windows and Towing pack.
Ordered 14 Dec 20, delivered 10 March 21
berryberry
Posts: 25
Joined: Mon Dec 30, 2024 7:04 pm

Post by berryberry »

We can confirm that Volvo have not accepted our rejection, as yet, but we will keep pushing until we get the just result.

As for the BCM, thank you for your input which is invaluable. We will go back to them today, but it was they who wrongly referred to it is a Brake Control Module. Your assertion makes far more sense to us, given what did occur on the night in question. Says it all, really.
riskymoth
Posts: 79
Joined: Fri Dec 08, 2023 2:17 pm

Post by riskymoth »

I managed to "stall" my MY24 B3 XC40 when it was still very new (late 2023) - I was approaching a car park accessed via a pot-holed gravel track, and came to a complete stop on the road before immediately starting moving again onto the track. The car engine stopped with the start-stop system, then immediately started again upon moving, and then stalled a split second later. It's never done the same since, so I always assumed one of the over-the-air updates would have fixed this issue. My previous Merc was also a 7-speed DCT, and I never managed to stall that - as someone said in a previous post, the only way to stall one is if there's a software or hardware issue - but I notice on a BMW forum there's a thread from some years ago where a certain model was experiencing the same, presumably now rectified by an update. In my case, it wasn't a life-or-death situation, and the car immediately started again when I pressed the button, so I didn't worry too much at the time...

Anyway, good luck with getting yours fixed, really sorry to hear you've experienced this - thank you for the updates.
berryberry
Posts: 25
Joined: Mon Dec 30, 2024 7:04 pm

Post by berryberry »

We did go back to Volvo to question the BCM issue and they advise that the car has a BCM (Body Control Module) and a BCM (Brake Control Module) - how clever is the person assigning acronyms?

They maintain they have been asked to check the second of these, but must admit we still believe that the first is more likely to have been involved. Meantime we await further feedback.
gripross
Posts: 421
Joined: Tue Oct 05, 2021 3:36 pm

Post by gripross »

Good luck and hope it doesn't drag on much longer
Ordered XC40 B4 FWD Ultimate in Vapour Grey 26/08/23 Factory Order Quoted 12 week Delivery
Delivered 24th January 2024

Gone XC40 B4P R Design Pro Pearl White factory order ( ordered 13/07/21) took delivery 18/10/21
berryberry
Posts: 25
Joined: Mon Dec 30, 2024 7:04 pm

Post by berryberry »

An update for those who had taken an interest in this topic....

Thanks are due to those on board who were so supportive in helping us push ahead with potential theories as to how this safety-related incident came to pass. This was critical, as by us persevering with these detailed theories, eventually the fault was found. It was the mid voltage converter module (MVCM), a critical component in hybrid technology (£1000 to replace), which was faulty.

What was astounding was that with our continuous refusal to accept back the keys when for 4 weeks no fault had been found, on the day of the fault code appearing, the master technician suffered a similar fate with complete loss of power, albeit in the relative safety of the forecourt. This could very easily have recurred on the open road.

It is now 6 weeks since the incident and only last week was our rejection finally accepted in what has been a thoroughly traumatic affair. Today we received 90% of our monies back and the fight goes on to get the remaining 10% as well as being suitably compensated for the whole episode. We have now had a hire car for 31 days and no-one will pay us for this, but our perseverance will come to the fore again.

We understand that the faulty car is being returned to Volvo UK along with the faulty module for further detailed analysis. It should be noted that Volvo Technical confirmed that they had seen this issue before.
Post Reply