XC70: Electrical Dashboard lighting up like a Christmas tree

[SynonymForTree]

My XC70 has gone very festive. https://imgur.com/a/nYHWwUG

I haven't had it very long and got it quite cheap with strong history - but maybe there was something the seller didn't tell me (or maybe something has just gone on it - it's high mileage after all).

This first started the other day when it was 0c outside - I got in, started it up and turned on pretty much everything electrical to heat the car. I noticed the lights and dash were flickering a bit - then the radio kept cutting out and the satnav would turn itself off and straight back on again. Then the DSTC light flashed on and straight back off again. I decided to take my other car which was already defrosted and put it down to it being cold + having literally everything electrical on in the car at once.

Since then it gets in this state when you first start it up - been in it twice. The satnav will pop up and down as it's clearly losing electrical connection - as will the radio and the lights will flicker. The warning lights on the dash typically stay off unless you start revving the car in neutral and then they appear. But once you've driven it for maybe 2 minutes, it all goes back to normal and runs perfect.

But then today towards the end of a 3 hour drive with it, while going slowly over some foggy hills, it started flickering on and off, same symptoms. It stopped and it was fine until I got home - when I started to pull up it started doing it again.

My hopeful and probably naive thought was that this seems to be alternator or battery related. I feel more likely the alternator because it starts perfect and the problem seems to go away when I start moving.

Worst case CEM or something even worse?

I'll add it doesn't have a sunroof and I've was very thorough to check for any signs of damp around the passenger footwell/seat when buying - I've since checked again and it's still bone dry after one of the wettest days of the year.

Has anyone seen anything like this before? I've done 0 diagnostics yet but will be starting by plugging in VIDA + checking voltage at the battery on the weekend. Any other tips appreciated.

[Pidgeonpost]

A failing battery can lead to Christmas lights dashboard display. Modern electrics demand that the battery is up to snuff. You could try giving the battery a full charge overnight or even 24 hours to see if that influences the problem, and checkout the battery to see if it has a date on it. Good luck.

[john.wigley]

Originally Posted by Pidgeonpost

A failing battery can lead to Christmas lights dashboard display. Modern electrics demand that the battery is up to snuff. You could try giving the battery a full charge overnight or even 24 hours to see if that influences the problem, and checkout the battery to see if it has a date on it. Good luck.

Sound advice there from 'Pidgeonpost', 'SFT'. We have three ageing cars that live outside and although we try to rotate them, the batteries have a hard time, especially at this time of the year. I have invested in a smart charger (mine was from Aldi and <£20) which I also rotate. Once it 'green lights', I know that it is fully charged and good to go. I also understand that it is kinder to the battery and helps to prolong it's life.

Regards, John.

[SynonymForTree]

Thanks both.

I'll start with the battery - I already have a Ring Charge and Diagnose Smart Charger which has done a good job on other batteries in the past for me.

I started it again today to drive 2 minutes to co-op and back. It was completely fine on start up and showed none of the previous symptoms. Today was much milder - perhaps an influence.

Will update the thread when I've had a look at the battery age, health and plugged in VIDA.

Still holding out to see if someone else has experienced the exact same symptoms as my video.

[Tatsfield]

My long term experience with cars with ECU system is that it isn't the cranking power of the battery which is necessarily deficient but the voltage stabilities for the system tests, while the starter is turning over, where the system sends known voltages to parts of the system and measures the return voltages on a pass/fail basis to light the fault lamps or note. I know dozens of owners of such cars where the battery operates the starter to turn over the engine but the warning lights come on and the owner cannot believe it is the battery at fault because it turns over the engine. While it is operating the starter against a huge load, the available stable power for the systems check is not stable or within range and so the return currents are also out of range and on comes the Xmas tree lights.

The advice given in my previous car club was to turn on the ignition and wait for the system check to complete before turning over the engine. If that stopped the warning lights, renew the battery so that it can cope with both the checks and starting the engine. The lesson learned is to always let the checks complete before turning the engine over. If the ECU is using voltage and voltage returned as a control of any systems while the engine is running and the car is being driven, the battery may not recover in time after starting the engine to provide the necessary check voltages. A new battery should solve that problem.

[Rob76]

I had this Christmas tree syndrome. Short story: Volvo owners club rep. for my model tried to help and talk to Volvo but they did not want to know. Battery monitoring is suspect on these cars. It was simply an alternator fault. For a few quid I bought a battery monitor for the Cigarette lighter, and I keep an eye on it. Cold mornings it gives a figure as high as 16.5 volts but drops rapidly to a more reasonable figure, a really long journey it has never gone below 12.5 volts. Worth every penny for piece of mind.

[SynonymForTree]

Originally Posted by Rob76

I had this Christmas tree syndrome. Short story: Volvo owners club rep. for my model tried to help and talk to Volvo but they did not want to know. Battery monitoring is suspect on these cars. It was simply an alternator fault. For a few quid I bought a battery monitor for the Cigarette lighter, and I keep an eye on it. Cold mornings it gives a figure as high as 16.5 volts but drops rapidly to a more reasonable figure, a really long journey it has never gone below 12.5 volts. Worth every penny for piece of mind.

Did you end up replacing the alternator and did that resolve it?

Or did you just keep an eye on it and it went away?

[SynonymForTree]

Quick update.

I tested the battery this morning - the car was last driven yesterday at around 3pm.

It was reading 12.3V. A bit lower, but enough to start. I couldn't find a fitted date on the battery but it had a recharge date of 2018, so I assume fitted in 2017?

I started it fine and it rose to 13V at first and then up to 15.3V. I was using a the smart charger to test it because I didn't have my multi meter to hand - so I was only getting a reading at a point in time, not live. The electrical flickering issue wasn't present at this moment.

15.3V seems high to me. I'm going to get an in car Voltmeter as suggested and monitor the Voltage when the electrical faults occur. Will also plug in VIDA when I remember how to get it working again.


Currently thinking a voltage regulator issue. Thoughts?

[SynonymForTree]

Did a VIDA Scan. Here are the results:
https://imgur.com/a/B3qesij

First two images are all the codes read when I first plugged it in. Cleared them and the final image is what still throws an error. Don't know about the windows, they all seem to work fine.

A lot of the historic ones all seemed to throw around 100 miles ago. Interesting that there are errors for both above and below Voltage threshold? Anyone seen this before and got any thoughts?

I'm still thinking voltage regulator or battery.

While it was plugged in VIDA was saying that car was at 15V while turned on. If my Voltmeter shows a different actual value then does that indicate the voltage regulator has gone?

[Simmy]

the first screen shot indicates lots of modules are struggling to work i would try a known good battery and reset the battery monitor . and see what it shows with a good battery use your vida as a diagnostic tool and look at the individual modules to find out what is happening with your car you can read alternator output with vida/