8.5R Gremlins

[Booth11]

Not a gremlin but a note of caution maybe.

 

A few days ago I had a plethora of warning lights and bongs go crazy, but I strongly suspected it was down to the battery being low (even though no low battery warning came up).
 

In the couple days days prior I’d been doing some detailing on the car with and only couple of very short journeys to and from the unit where I was working and only short journeys in the days before that. I think the final straw for the car was, on one short journey the post detailing session, I had Airconsole running on from the VW Shop and sat in a car park playing a trivia game whilst my daughter was getting a coffee and then when she returned she wanted to play.  That was it, on ignition start up it was Bongtastic all the way home!  
 

I took the car out for a good long run and after a few miles the warning lights disappeared except the engine light, which stayed on until the battery was sufficiently charged and then went off at the next startup.  
 

My own fault and I should have preempted it, but I do find with the mk8/8.5 compared to previous Golfs, that it doesn’t that having the ignition on, without driving, for the battery voltage to drop. 

 

[Phil2025]

If the battery can supply something like 100amp to crank and start the engine then there is nothing wrong with the battery, and I'm afraid its wishful thinking on our part to think its something as simple as that.

 

The Golf 8.5s will give a "Low 12 volt warning, consult the manual" on the dashboard if the battery is a bit off the boil, i.e. not had a recent or decent drive and then having sat in it for a while before starting the engine.  I've had umpteen of these warnings, especially during the colder mornings, and know from having used an intelligent charger when its happened, that the battery isn't anywhere near flat, hence its never failed to start the car and never shows any sign of being flat when cranking the engine, and I've never had any other errors reported.  So I would think if the battery was in anyway a bit low you'd have seen this warning first.

 

Whilst I'm sure a fully charged battery, or replacement battery by the dealer helps hide some these issues for a while and looks like the cause and the fix, it really isn't what is causing these problems, and a car battery should last longer than a few months.

 

Hoping it was just a one of software glitch for you and it doesn't happen again.

[mahalo]

I recollect that Rebecca had issues with the battery on her previous Mk 8R and it was replaced under warranty - it is suspicious that there now appears to be issues with the battery on her Mk 8.5R.  The post by phil2025 above makes perfect sense  in particular if the battery can start the car easily then it cannot by definition be drained/flat. 

Most of these car sensors and microcontrollers in the Golf 8R and 8.5R will not be running on 12v but on 5v or 3.3v and there will be one or more voltage regulators which will step down the 12v main power supply to the required voltage. All voltage regulators are not the same and I wonder if they are misbehaving if they get a slightly low voltage on the 12v input side.  The 12v battery low voltage warning will be initiated by a sensor across a particular circuit and will be set to trigger at a certain level.

Adding extra electrical load to particular circuits (dash camera setup which I think rebecca has done ) may very well affect this electrical balance which perhaps might be a cuase of such behaviour as seen.

On my Mk 8R i left the car in airport car parks for sometimes up to a month and had no problems with starting car or battery being low. Prior to each such event I would take precautions by charging the battery up to full. Similarly when I first got the Mk 8.5R it was left in an airport car park for nearly a month again with no issues.  

[Booth11]

Thanks @Phil2025 and @mahalo.

 

The battery was obviously not flat in this situation given the car started, but the behaviour with warnings etc is consistent with my experience of previous low battery behaviour throwing up a multitude of errors, but take on all your points.  I may be wrong in assuming that’s the issue but have had similar experience with previous two cars when battery was low.  
 

In both my mk8 and mk7 I had dashcam fitted and had to have batteries replaced under warranty, and I suspect that the dashcam was a factor in that. I haven’t fitted a dashcam yet in my 8.5R so that cannot be considered as an impact here.  

 

Will just have to monitor the situation.  I’ve had one low battery warning on the dash a few weeks back when the car was not being used much.  But nothing came up on this occasion.  I have had no other errors since getting the car back in Dec last year. 

[AHG]

5 hours ago, PBHorne said:

You have to reboot the system for it to reconnect properly again

 

What if you just reconnect it from the screen ?

or turn WiFi off on the phone and connect by wire ?

or just turn the screen off an on (or the car) instead of rebooting the info system ?
 

Would any of those work ? 

Disconnecting is explainable (just physics).

So my questions are meant to isolate the culprit that prevents reconnecting, which is the strange issue (shouldn’t happen) and maybe figure out the weak link in the chain.

 

one explanation I can think about, especially if it happens in a specific geographical location, is that something is interfering with the signal and the phone’s security protocols ignores that specific “call out” to avoid risk.

When you reboot, the call out from the car may be new (by some random generator) so the phone can accept it.

 

Just a theory, not corroborated, yet.

[AHG]

2 hours ago, Phil2025 said:

Whilst I'm sure a fully charged battery, or replacement battery by the dealer helps hide some these issues for a while and looks like the cause and the fix, it really isn't what is causing these problems, and a car battery should last longer than a few months.

 

It’s may be the case that the software is designed for when engine is on, and so it checks for charging currents, and when they are missing it starts reporting errors. This is ill design for sure, but may not be a malfunction of any specific system, just a wrong guided logic of design, or poor integration and risk analysis in the process (which I think is why we got the steering wheel bongs and screen black outs, but I have no data to support it).

[AHG]

1 hour ago, Booth11 said:

I’ve had one low battery warning on the dash a few weeks back when the car was not being used much.

I think we should separate between “trigger” and “cause” (or faulty part/code).

 

From the combined information given here over the years, I get the understanding that there are many points of faulty design (of algo/logic, mainly) that usually don’t show unless combined with triggering factors (such as semi-low battery, or fluctuation in current, cold weather, steering wheel signal inconsistency, etc).

 

You can “fix” or avoid the trigger (change steering wheel, keep the engine running) but he root cause is still there and may be triggered by something else at some point (or the trigger will come back, like in steering wheels).

 

It is like when a plane malfunctions due to a storm.

The storm may be the trigger but it is not the malfunction.

Something didn’t hold up or operate the way you’d want it to, in lieu of the heightened rate of events or loads, brought on by the storm.

May be structural that needs to be reinforced, or electronics that need better shielding, or control arms and motors that need to be stronger to oppose strong wind.

So if you avoid storms it may not happen, but it may be triggered by something else (manouver, for example), because the storm is not the root cause of the fault, only its trigger.

Sorry for the length of this response, but I think it is an important distinction that may aid us moving forward, if we have any control over what happens.

 

For example, if someone tells me they changes steering wheel due to false alerts popping up and it came back, I’d say a new £1,000 wheel just buys you some time because your system is sensitive to it (some are not, for some reason) and it probably will come back.

So, if we don’t know where the sensitive part is so they may want to get a different car (it it’s a statistical game, odds are the second will be different) or disconnect the trigger somehow (KLR module, coding or whatever).

[mahalo]

I am surprised that in either of my Mk 8R and Mk 8.5 R I have never experienced an issue with low battery - I don't tend to do a lot of miles and the car can be sat for extended periods without being driven.  A lot of the drives that I do are also short drives so this type of usage you would suspect would lead to battery being low issues. As I stated in my previous post, all these sensors like lane assist, front assist etc operate on either a 5v or 3.3v so will have voltage regulators in these circuits to regulate the voltage down from 12v to the required voltage. I have not looked at an electrical schematic for how the Golf is wired but it would not surprise me if there was a common voltage regulator/ microcontroller involved for these circuits. If the voltage regulator/microcontroller  does not, under certain conditions, provide the right voltage to these sensors then they will display fault signs.  

[Booth11]

21 minutes ago, AHG said:

I think we should separate between “trigger” and “cause” (or faulty part/code).

 

From the combined information given here over the years, I get the understanding that there are many points of faulty design (of algo/logic, mainly) that usually don’t show unless combined with triggering factors (such as semi-low battery, or fluctuation in current, cold weather, steering wheel signal inconsistency, etc).

 

You can “fix” or avoid the trigger (change steering wheel, keep the engine running) but he root cause is still there and may be triggered by something else at some point (or the trigger will come back, like in steering wheels).

 

It is like when a plane malfunctions due to a storm.

The storm may be the trigger but it is not the malfunction.

Something didn’t hold up or operate the way you’d want it to, in lieu of the heightened rate of events or loads, brought on by the storm.

May be structural that needs to be reinforced, or electronics that need better shielding, or control arms and motors that need to be stronger to oppose strong wind.

So if you avoid storms it may not happen, but it may be triggered by something else (manouver, for example), because the storm is not the root cause of the fault, only its trigger.

Sorry for the length of this response, but I think it is an important distinction that may aid us moving forward, if we have any control over what happens.

 

For example, if someone tells me they changes steering wheel due to false alerts popping up and it came back, I’d say a new £1,000 wheel just buys you some time because your system is sensitive to it (some are not, for some reason) and it probably will come back.

So, if we don’t know where the sensitive part is so they may want to get a different car (it it’s a statistical game, odds are the second will be different) or disconnect the trigger somehow (KLR module, coding or whatever).

I don’t think at this stage we can isolate trigger and cause.
 

I suspect that the low battery warning I had a few weeks ago (first indication prior to seeing the dash warning was the keyless not working), was a combination of lack of driving the car any distance that week, but still accessing it to shift it around on my driveway for reasons too mundane to detail here.  Lots of door opening, ignition on and just shunting the car here and there.  This was followed by normal use and no issues.  This last weekend there was similar shunting about usage, doors opening and closing etc, plus a period accessing infotainment without the engine running (which I don’t normally do), and after that the bongs and warnings with a variety of systems not available (such as auto hold, ACC, Assists etc.  All has been normal  

after my long drive and now back to normal use again.  

[PBHorne]

1 hour ago, AHG said:

 

What if you just reconnect it from the screen ?

or turn WiFi off on the phone and connect by wire ?

or just turn the screen off an on (or the car) instead of rebooting the info system ?
 

Would any of those work ? 

Disconnecting is explainable (just physics).

So my questions are meant to isolate the culprit that prevents reconnecting, which is the strange issue (shouldn’t happen) and maybe figure out the weak link in the chain.

 

one explanation I can think about, especially if it happens in a specific geographical location, is that something is interfering with the signal and the phone’s security protocols ignores that specific “call out” to avoid risk.

When you reboot, the call out from the car may be new (by some random generator) so the phone can accept it.

 

Just a theory, not corroborated, yet.

No unfortunately not. I tried a multitude of ways to reconnect. The last resort was trying the reboot, that's worked 3 times for me now. 

 

 

[Scudgie]

10 minutes ago, Booth11 said:

I don’t think at this stage we can isolate trigger and cause.
 

I suspect that the low battery warning I had a few weeks ago (first indication prior to seeing the dash warning was the keyless not working), was a combination of lack of driving the car any distance that week, but still accessing it to shift it around on my driveway for reasons too mundane to detail here.  Lots of door opening, ignition on and just shunting the car here and there.  This was followed by normal use and no issues.  This last weekend there was similar shunting about usage, doors opening and closing etc, plus a period accessing infotainment without the engine running (which I don’t normally do), and after that the bongs and warnings with a variety of systems not available (such as auto hold, ACC, Assists etc.  All has been normal  

after my long drive and now back to normal use again.  

 

Dare I suggest you're cleaning your car too often, Rebecca? 🤣

 

All very valid observations but, for me, the plethora of control modules that a modern car now possesses means that it's obliged to provide a warning if there's any issue, regardless of seriousness, impacting its operation - such as voltage drop, fogged up windows etc etc.

 

 

[Booth11]

36 minutes ago, Scudgie said:

 

Dare I suggest you're cleaning your car too often, Rebecca? 🤣

 

All very valid observations but, for me, the plethora of control modules that a modern car now possesses means that it's obliged to provide a warning if there's any issue, regardless of seriousness, impacting its operation - such as voltage drop, fogged up windows etc etc.

 

 

 

Undoubtedly John.  😂  But when I clean my car it stays in one position aside from a minor move to enable access to the hidden area of tyre and wheel barrel.  It doesnt get moved about really, and often I take it for a spin afterwards.  The recent occurrences of driveway shunting are not connected to car washing but are in connection to minimising impacts from a nearby facility but I'd rather not say exactly what as that's divulges specific location. I'm not being intentionally mysterious - it's quite a specific set of circumstances (and not particularly interesting).  😄

 

I agree with you that all this new fangled tech is designed to throw up a warning if something like a low battery voltage impacts it, and judging by the systems that throw errors, they essentially secondary ones, unless of course the battery actually goes flat. 

 

I'm not concerned as I think that this is the reason and I have experienced it before.              

[blizzard60]

It's low voltage almost certainly, and definitely nothing to worry about as you said from the beginning with your "not really a gremlin". You've hit the nail on the head. I never too your post as the battery was flat, or else, as you said, how would have started the car and driven home!! Please do keep us posted, as you and many others have said, the multitude of crazy tech just leads to speculation because of all these "errors".

 

15 hours ago, mahalo said:

I am surprised that in either of my Mk 8R and Mk 8.5 R I have never experienced an issue with low battery - I don't tend to do a lot of miles and the car can be sat for extended periods without being driven.  A lot of the drives that I do are also short drives so this type of usage you would suspect would lead to battery being low issues. As I stated in my previous post, all these sensors like lane assist, front assist etc operate on either a 5v or 3.3v so will have voltage regulators in these circuits to regulate the voltage down from 12v to the required voltage. I have not looked at an electrical schematic for how the Golf is wired but it would not surprise me if there was a common voltage regulator/ microcontroller involved for these circuits. If the voltage regulator/microcontroller  does not, under certain conditions, provide the right voltage to these sensors then they will display fault signs.  

 

Hey, every module in both the MK8 and MK8.5 is 12V unless you have a 48V system Golf.

They ABSOLUTELY may step-down the voltage internally, I am definitely not aware of that (or not), but power is supplied to them at 12V.

 

J428 ACC Radar and R242 driver assist camera (lane assist) get 12V from fuse SC58

J527 Steering column control module gets 12V from fuse SC45 and SC39

 

I have had most modules from these cars on my bench and all of them powered from 12V and I was able to connect to them and communicate/flash them.

 

There are no voltage regulators within any of these circuits.

[Booth11]

5 hours ago, blizzard60 said:

It's low voltage almost certainly, and definitely nothing to worry about as you said from the beginning with your "not really a gremlin". You've hit the nail on the head. I never too your post as the battery was flat, or else, as you said, how would have started the car and driven home!! Please do keep us posted, as you and many others have said, the multitude of crazy tech just leads to speculation because of all these "errors".

 

 

Hey, every module in both the MK8 and MK8.5 is 12V unless you have a 48V system Golf.

They ABSOLUTELY may step-down the voltage internally, I am definitely not aware of that (or not), but power is supplied to them at 12V.

 

J428 ACC Radar and R242 driver assist camera (lane assist) get 12V from fuse SC58

J527 Steering column control module gets 12V from fuse SC45 and SC39

 

I have had most modules from these cars on my bench and all of them powered from 12V and I was able to connect to them and communicate/flash them.

 

There are no voltage regulators within any of these circuits.

Thanks for your insightful and valuable input @blizzard60.  Will definitely update if anything else transpires.  I’ve learned to be quite relaxed about warning and errors in the mk8/8.5 over the years. I’m no expert at all, but you tend to get a sense for what is a genuine warning, what is potentially a genuine fault; and what is a warning in relation to low battery voltage etc.  

[mahalo]

6 hours ago, blizzard60 said:

It's low voltage almost certainly, and definitely nothing to worry about as you said from the beginning with your "not really a gremlin". You've hit the nail on the head. I never too your post as the battery was flat, or else, as you said, how would have started the car and driven home!! Please do keep us posted, as you and many others have said, the multitude of crazy tech just leads to speculation because of all these "errors".

 

 

Hey, every module in both the MK8 and MK8.5 is 12V unless you have a 48V system Golf.

They ABSOLUTELY may step-down the voltage internally, I am definitely not aware of that (or not), but power is supplied to them at 12V.

 

J428 ACC Radar and R242 driver assist camera (lane assist) get 12V from fuse SC58

J527 Steering column control module gets 12V from fuse SC45 and SC39

 

I have had most modules from these cars on my bench and all of them powered from 12V and I was able to connect to them and communicate/flash them.

 

There are no voltage regulators within any of these circuits.

Thanks for this - I have managed to find the Golf Mk 8  wiring diagrams and yes it looks like they all being fed 12v. J329 regulates the power on SC58. The battery monitor(J367)  is just connected  directly to the battery so will just measure a straight battery voltage drop across the battery.  

I wonder how J519 and J533 react if the battery voltage drops.