2015.5 xc60 t6 random loss of all power after turning car off

wwwvvvggg · Post by **wwwvvvggg** » 10 Mar 2020, 20:22

2015.5 xc60, single owner, engine replacement at 49K. The car has70K today and recently had rear bumper repair from rear end accident. We have a new issue that started afer body repair and the dealer has been unable to solve.

Occasionally, like every 15 days, after parking, the car does not have any electrical current, will not start, dashboard doesn't light up etc. If we wait 8 hours, the car starts again or if we disconnect the battery terminals, it sometimes restarts faster.

The battery has only 15k miles on it, has a full charge, and is high quality. All terminals have been cleaned and wiring has been checked. It is like it takes a short rest break. The dealer said the issue was fixed but it keeps happening. Anyone have any ideas on how to investigate further? I would really appreciate any ideas.

Post by **jimmy57** » 10 Mar 2020, 20:43

Has it ever done this while the dealer had it for repair?
If you repeat the problem there is a check I would do if I were working on it while it not powered up. Remove the back battery cover to access the ground (-) terminal and cable end. with car exhibiting the no electrical power check from battery post to engine block or good chassis connection. There should be a reading of 0V but if the battery monitor sensor on the negative cable end at battery negative post is faulty then you will read 12V between post and chassis or engine. I am assuming the issue was before and after the new battery. There can be a failure of battery internal cell connector that can make battery go open and then recover later. Usually that kind of internal battery problem will only do that few times before it fails completely. The stop/start switching unit by the secondary battery in under wiper/cowl cover could conceivably kill electrical power but I have not heard of that as a failure and it would likely be connections and only affect some items in car.

wwwvvvggg · Post by **wwwvvvggg** » 10 Mar 2020, 21:01

thank you very much for quick reply. Has happened more "instantly" lately with new battery but nothing in first 3 months new battery. Lots of issues with old battery saying low battery, various messages and did fail a few times but was able to be jumped. All of that stopped with new battery. I had read about start/stop switch maybe having something to do with so we have that turned off. Regardless, this sounds like a great way to check and will do next time it happens. Unfortunately, and of course, never happened at dealer. Would you mind explaining what "open and then recover later means". Appreciate the feedback and will re-post when solved or more color.

Post by **jimmy57** » 10 Mar 2020, 21:52

If the internal connection goes open that means the connection is broken and there would be no voltage measured at battery terminals. WHen that happens the connection can cool off and then battery has power at terminals again.

wwwvvvggg · Post by **wwwvvvggg** » 12 Mar 2020, 21:03

Yes, as we have thought about it, you must be right. It only happens when the battery is hot, meaning when we have stopped the car for a short amount of time and try to start it again. It never happens in the morning, or after the car has been off for a long time. We're going to replace the battery and let you know if it worked. Thanks so much for forcing us to think in the right direction!

XC60Rpolestar · Post by **XC60Rpolestar** » 22 Mar 2025, 21:24

Check the fusible link on top of the positive battery terminal assembly
These had a known problem this was a factory update recall that happened on the 2015 models. (Most of them were replaced before they made it to the dealerships, but some of them slipped through) of cracking due to thermal cycling or handling the positive battery cable assembly during battery install and replacement the fusible link inside the little square black plastic box becomes partially and then mostly broken through and can cause total loss of power feed to the car.

look up fusible link on the site and you will see a couple of workarounds for less than $20 that other Volvo owners have Put in place.
Hope this helps just did same repair
Jack
2015.5 T6R Polestar

Vova585 · Post by **Vova585** » 23 Mar 2025, 19:40

I would not rush to replace battery. If the battery would be dead you would not be able to start it in 8h as you suggested. It is not a paralytic draw since once again you able to start the car without having to charge the battery between episodes of "no start, no dash light" and once again all is ok. Same as jimmy57 and xc60rpolestar I would suspect problem with main battery leads/wires. Fuse link is a common issue and easy to be fixed(just replace entire cabel and be done with it). If you want to check battery theory-invsst in gooloo Jumpstart($100) and have it with you in a car junk in case it will happen again and see if with jump pack it will start. If jump pack is not helping the issue-invest Into decent set of jump wires and during the episode of no start connect "-" of the battery to the engine ground and see if something changes. If not-your issue is more than likely that fusible link