IS250 2010 - DAB not working first thing in cold weather

[Razor61]

I have had the IS250 for 3 years now, it was my car for the first 12 months then the Mrs car after that.
Ever since we had had the car the DAB radio bit did not work first thing in the morning when it was very cold, after driving the car for a few miles - stop - switch off - start again and the DAB radio worked ok.
Spoke to Lexus and they have never heard of the issue and said it would be difficult to diagnose which I fully understand so never had it checked out by them and didn't start looking myself.
FM/AM and CD still worked along with everything else and it only happened when the weather was just above freezing by a few degrees with a frost or below freezing. So the vast majority of the year it wasn't an issue.
The issue has got worse recently though and happening at higher temps 4 or 5 degrees.
However, on New Years Eve the car was struggling to turn over/start but it did just start, new starter Battery required and planned to get one from Lexus on 2nd Jan.
New Years day it would not start at all, lights on etc but wouldn't turn over so Battery ordered from Lexus on 2nd Jan and had to wait until the next day to get the Battery (Wednesday). Battery collected from Lexus and fitted it that day, all good and car starts no problem.
Why am I relating this story of replacing the starter Battery you may think, well over the weekend the weather was just above freezing and today below freezing at -3 degrees.
Saturday I started the car in the morning when it was around 1 degree and a thick frost, hey presto the DAB radio worked straight away and I was very surprised. Maybe it hadn't been cold enough for the issue to happen I thought.
This morning I needed to drive the IS250 to work, pavement has been dug up at the end of the drive so can't take the LS400.
It was -3 degrees and the DAB radio worked straightaway again, this time I was very very very surprised. I guess changing the starter Battery for a new one has solved the issue.
Maybe the Battery has not been 100% since I bought the car, has been a bit weak and very cold weather made it worse (as normal for a dodgy battery) causing the DAB issue in some way. Can't see how or why though but with auto electronics nothing surprises me.
Changing the Battery itself, so in effect a 'reset', wasn't the fix because quite a while ago, maybe 2 years, the Mrs managed to leave the headlights on and lock the car somehow and flattened the Battery. Car was beeping like mad at her apparently but the beeps were ignored and the car locked somehow with the lights on. Battery was removed and charged up by me so the car had a 'reset' then.

[Beamish]

 

Thanks for posting this Paul.

I'm happy that your problem is sorted.

It really is interesting to hear of the myriad ways that a failing Battery seems to effect these cars.

 

Dec.

[Mr Vlad]

Absolutely. One has to keep on top of the condition of the cars Battery. 

If I were you I'd regularly, as in daily, measure the voltage of the Battery and at the same time of day. With the age of these cars now the alternator may be showing signs of dying. As an example. My beloved is250's alternator packed up at around the 85k mile mark. And my car had a 100% dealer service history. Just a thought.

[Cotswold Pete]

Heck almighty, really strange story this one. 

Glad problem solved but would have been interesting to see what the old Battery was reading before you cranked engine. 

The voltage of a car Battery should be between 12.2 to 12.6 volts when the engine is turned off. A fully charged car Battery voltage falls between 13.7 and 14.7 volts with the engine running. With the Battery charge at 75%, the voltage can drop to 12.4 volts. At 25% charge, the voltage will measure around 12 volts. 

The LS400 is more tolerant of Battery on the way out from my experience.

[Razor61]

I spoke too soon, snow this morning and the end of the drive is still 'dug up' so took the IS250 to work. -2 with snow on the car and DAB didn't work. Drove to work, switched off, switched on (didn't start the car) and DAB working. I really did think the issue was solved but sadly not.
Back to the drawing board, if I decide to do something about it.
Thanks for your comments.
I'll check the Battery voltage and check the voltage across the Battery when running, maybe the alternator is showing signs of dying, my instinct tells me it isn't but it is a possibility, as Vlad says.
I don't drive it daily but I will check out the alternator, if I had a scope I could check the rectification is working ok and there is not too much DC ripple. Maybe the running voltage will give me a clue though.

[Razor61]

-3, very cold and very icy this morning, the DAB radio worked fine 🤷‍♂️ strange but true..........

[Cotswold Pete]

41 minutes ago, Razor61 said:

-3, very cold and very icy this morning, the DAB radio worked fine 🤷‍♂️ strange but true..........

My guess would be a dry joint somewhere. which would be a bit of a do to spot even if you took the radio out.  Slight possibility of some loose push connector on the board, or worse a dry joint on base of the connector socket (seen lots of these in the days when I delved into the circuits)

 

[Razor61]

4 hours ago, Cotswold Pete said:

My guess would be a dry joint somewhere. which would be a bit of a do to spot even if you took the radio out.  Slight possibility of some loose push connector on the board, or worse a dry joint on base of the connector socket (seen lots of these in the days when I delved into the circuits)

 

Yep, it's likely and was my first thought right in the beginning but it would be a radio out job so never bothered and it's not the car I drive daily anymore.
I was in electronics repair years ago, TV/Video/Audio/Computers etc. so I've done my fair share of finding dry joints and broken tracks with freeze spray, and/or a toothbrush plus wiggling the component leg. I would consider buying a used unit and replacing it but it may not be the assembly itself.
If I did pull the satnav unit, I would need to check all the joints or re solder everything I can get to, unless I am lucky and it's an obvious dry joint or there is the telltale 'ring' on a joint. I may pull the satnav assembly and check the connectors and connector joints but that would be it, I'm not going to strip it down for an issue that occurs in winter a few times. Anyway, the components will be very small and most will be surface mounted, compared to components with legs going through the board which I can still see ok and work with. Different world now with electronics.
It's only me that notices it anyway, the Mrs just uses FM and doesn't notice DAB isn't working.
When the issue does happen, the Audio is 'off' when the car is started and displays 'Audio Off' on the display. I suspect the unit doesn't know what to do when it tries to power on in the 'state' is was powered off, DAB working, and when DAB isn't there anymore it powers off. I think it has got 'better' for some reason to be honest.