Urgent help needed please

[wynnj]

Started the car this afternoon (XC60 D4 MY18), turned it round, drove about 100m and as the auto wipers started, various warnings started flashing on the driver's display, starting with brake light system malfunction. I immediately pulled over and switched off the engine but when I tried to restart it - nothing. However, by now the driver's display was illuminated like a christmas tree but I could do nothing. The wipers went into very fast then gradually over about 20 mins slowly dropped to normal speed, intermittent then off. The car won't lock the horn won't operate but the radio continues to work but not turn off. I can't get into the boot as none of the controls operate to release the catch. I can't lift the boot floor from inside to disconnect the battery as it catches on the liner of the tailgate.

I got the car transported home in the hope that I could fault find with my OBDlink MX+ but although it identifies the car correctly it says no codes, but this may be because I can't start it - I've not used it before.
I also plugged in my old BSR PPC Volvo specific Code Reader but again no codes identified.

The recovery driver did connect his jump starter in case it was battery but nothing changed, but I'm not surprised as the main battery has always been good, although I suspect the secondary battery may be close to end of life as the auto stop start doesn't function, however, I don't want that and it saves me having to switch it off on the centre display.

So in conclusion I've got a car with the driver's display illuminated like a christmas tree, the radio operating, can't lock it and can't open the tail gate

I had the SW for a volvo towbar installed last Tuesday but driven 60 or 70 miles since then with no problem, and all the towbar functions seemed OK, so this may be a red herring.

Ideas of where the problem lies and how to fix it please.

Apologies for the long post but wanted to give as much info as possible.

[Simmy]

sounds like a battery problem or a loose or semi broken connection.

[bluebarchetta]

I agree with Simmy, look for a loose earth or power cable.

[Carabind]

If someone else installed the software, might be worth calling them back as it’s happened soon after they’ve done it. Maybe they’ve disturbed a connection or earth

[OldEngineer]

I'd be looking for a disturbed Earth from that tow bar fitting. Might be enough to get it going after the fitting but now too loose.

Remember, when you get warnings of multiple failures it can't be those items all failing at exactly the same time. It means each item has failed the voltage check. If the plus side of the battery works it will be the Earth side.

[wynnj]

Thanks to all who've replied.

Re tow bar earth, there was only one lead and that was fixed securely to the designated earth post. Unfortunately I can't get at it as I can't open the tail gate and can't lift the boot floor plate as it fouls the tailgate liner. P.S NOW DONE!

I'd half convinced myself that this was caused by sudden catastrophic failure of the support Stop/Start battery, however I've now taken the cover off this and it reads a steady 12.8 v so that would appear to be OK. However across the charging post I'm only reading 2.4 v implying the main battery is now pretty well fully discharged because of all the systems left active such as the radio, blower etc when everything failed. I think it read 11.4 v on the OBD link reader yesterday not long after the car was brought home. So it doesn't look as if the primary battery was the initial cause, and 11.4v should have been enough to open or lock the car if these systems hadn't already been shut off.

By the way I forgot to add yesterday that whilst broken down at the side of the road I couldn't activate the hazard warning lights either; great safety feature when you're broken down but can't warn anyone!

I'm now undecided whether to recharge the main battery from under the bonnet or leave it till it drops even further before trying. The fact that it's dropped so low implies there's still a load across it.

I read on one of the forums of someone having to have a new CEM because of multiple system failure but it turned out it was the DEM that had failed and pulled everything else down. Anyone any experience or thoughts on this and how I might check it out? I add this also because I had done a three point turn just before all this happened, but nothing extreme or heavy footed.

Any further pearls of wisdom greatfully received.


P.S. I'VE NOW FOUND A WAY TO REMOVE THE TAILGATE LINER IN SITU AND HENCE THE BOOT FLOOR SO WILL NOW REMOVE THE EARTH SIDE AND CHARGE THE BATTERY

[OldEngineer]

All charging should be done from under the bonnet so that the BMS knows what's happening.

Interesting that you were doing a 3 point turn at the time. The electric steering pulls the most current in the car which would reveal a poor earth.

First get the battery back up to full strength then check for a resistance (or a load)

[wynnj]

Originally Posted by OldEngineer

All charging should be done from under the bonnet so that the BMS knows what's happening.

Interesting that you were doing a 3 point turn at the time. The electric steering pulls the most current in the car which would reveal a poor earth.

First get the battery back up to full strength then check for a resistance (or a load)

Thanks OldEngineer. Once I'd got to the battery I disconnected the negative and put it on charge directly across the terminals. I wanted to isolate all the electrics and systems from the main battery so that hopefully everything will reset (like switching off to reboot a PC). I will now reconnect main battery and continue charging via the post next to the auxilliary battery.

Although still reading 12.8 volts I've also now removed the secondary battery and put that on charge separately on the basis of trying to start from scratch with two fully charged batteries.
I'm assuming I can still charge the main from under the bonnet with the secondary removed.

Hadn't thought about the steering being the cause. Food for further investigation certainly (excuse mixed metaphor!) but I've obviously used full lock many times before and had no problems. Don't know where to start checking bad earths or permanent loads though.

[rmvm]

For what its worth. I had a 2021 V90CC with 3 weeks since taking deliver everything went completley dead, nothing would work, couldn't get in the car. I sent for roadside assitance from Volvo, the engineer immediately recognised the second battery in the boot has the problem. He managed to get into the car via the metal key in the key fob and completely disconnected the battery (both live and earth leads) and then waited a few minutes and magically everything worked and had been faultless upuntil we sold the car in March this year. I hope you resolve the problem soon. Cheers Roy

[wynnj]

An update of progress so far, if only as an archive if someone has similar problems in the future.

As soon as I reconnected the main battery the car sprang back to life and I was able to start it. Switching off and restarting a second time, however, resulted in identical failures to the original problems. Eventually got a laptop connected and read the codes with VDASH which, not surprisingly, was a list as long as your arm including several relating to the Trailer Module TRM. (see attachment)

I then decided to disconnect all the trailer electrics, and so far at least, the car has returned to normal apart from a pop up on start up telling me a trailer service is required because the SW no longer has a TRM to communicate with.

Next stage is get in touch with FRF in Swansea and see what they say and whether I can return it all as it's not obvious whether the problem lies with a failed electronics module or something in the wiring to the towball itself.

If anyone has the wiring diagram for the towbar electrics I'd be grateful for a copy as I'd like to understand how the retractable release mechanism works and whether it's possible to contine to use the volvo towbar, assuming that's OK, with aftermarket electrics.