Mk7 Stop/Start System - Issues and Questions

[Lemonskin]

Anyone else had this? Popped up on my trip back from the south coast today. Remedied by turning the car off and on again but I hope it's not some underlying problem that will give me grief.


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[DV52]

Anyone else had this? Popped up on my trip back from the south coast today. Remedied by turning the car off and on again but I hope it's not some underlying problem that will give me grief.

Lemonskin: Have you tried touching the area of the screen where the error message is displayed? I just wonder whether in doping so, you would get a better explanation of the fault.

[kevcol]

I presume most users turn their stop start system off at night due to the added load of the lights on the battery.
I also guess the batteries used are similar to "deep cycle" batteries used with solar panels that can be discharged deeper and more often than standard batteries which can tolerate only shallow cycles.
As an aside I wondered what VW regenerative braking was until I read it had nothing to do with the brakes but was just control of the alternator so it does not charge when accelerating.
The world desperately needs a replacement for lead acid battery technology.

[Eaglehawk]

I presume most users turn their stop start system off at night due to the added load of the lights on the battery.

A Despicable Me minion's "Whaaaahh?"

[DV52]

I presume most users turn their stop start system off at night due to the added load of the lights on the battery.
I also guess the batteries used are similar to "deep cycle" batteries used with solar panels that can be discharged deeper and more often than standard batteries which can tolerate only shallow cycles.
As an aside I wondered what VW regenerative braking was until I read it had nothing to do with the brakes but was just control of the alternator so it does not charge when accelerating.
The world desperately needs a replacement for lead acid attery technology.

keycol: The mk 7 uses what's called an EFB, (Enhanced Flooded Battery) which is a little different to the normal wet-cell batteries in cars (these days, these are mostly AGM, - Absorbent Gas Mat batteries) . If you pull-up the battery "cossie" and you look at the top of the battery, you should see the word "EFB" on the battery, (see pic)

EFBs are more suited to stop/start cars because they have better "Cycle Resistance" and they have better "Layer Resistance"

On a EFB the positive plate inside the battery is coated with an extra polyester fabric. According to VW's literature, "this gives the active battery mass additional grip on the plate". This increases "Cycle Resistance" which is the number of cycles of charge/discharge before the performance of the battery is compromised. In this way, the EFB is more compatible with Stop/Start because of the continuous cranking cycles.

The other feature of EFB is the use of passive mixing elements in the battery which allows a better electrolyte circulation. What this does is to better combat what's called "Battery Layer Resistance" which happens when the battery experiences severe discharge (this causes unequal acid concentrations to occur at different parts of the battery which results in the electrolyte being deposited on the plates - causing lowered battery performance.)

So, whilst I understand your concern about the additional load on the battery at night (this would normally be managed by the Battery/Alternator working together), I'm not sure that you actually need to switch-off S/S.

My view is that there are much better reasons to switch off S/S ALL THE TIME. I reckon that S/S is the most dangerous thing in the car. I disabled it long ago (VCDS tweak)

[turtle]

Had a problem with the SS system on my GTI PP ever since I've had it (about 6 months). Like other people on here have said, sometimes when you come to a stop the system won't work at it show an error of "Engine must be running for SS system to work". Sometimes cycling the shifter to Park then back to Drive cures the problem. The problem only happens every now and then. In fact its been fine for weeks then today it happened on my way home from work.
Any clues on what could be wrong with it? I mentioned it to the dealer when the car was there for an unrelated issue and they said they couldn't find any faults.

[firstvw]

start/stop feature - does not auto restart after stopping at traffic lights.

MK7 DSG Comfortline, 30k on the speedo, just had my 24months service a month ago.

Driving with start/stop active. Car stops at traffic lights (or intersection) and engine turn off. Once ready to go I lift foot of brake and step on accelerator and the car auto restarts normally BUT in these few weeks the car tries to start but it does not start. So I have to put the gear back to P and restart manually. It has happened around 6 times already.

Is anyone having a similar problem ?

[dero]

Take it back to the dealer and get it fixed under warranty.

It could be a faulty starter motor.

[firstvw]

Just booked my car in for a look at the start/stop this week. Will update once...

[sillyboy]

Car takes alot longer to engage into 1st gear when I stopped on a slight uphill slope, is this normal?

I stopped using this S/S function after I found out some blown up turbos were cause by the S/S, I wish I can find someone in my area with VCDs to disable it.

[firstvw]

Update, after leaving my car there for a day, vw could not find any issues. Battery was tested, all firmware is up to date.

Funny thing was it did not happen all all on the way to the dealer or a few days afterwards. However it did happen once yesterday. I will leave it until it gets worst.

[Imolator]

Update, after leaving my car there for a day, vw could not find any issues. Battery was tested, all firmware is up to date.

Funny thing was it did not happen all all on the way to the dealer or a few days afterwards. However it did happen once yesterday. I will leave it until it gets worst.

I don't like the idea of using stop-start with Turbo engines, I'm probably being overly paranoid but I'd rather have oil flowing than worry about damage from heat soak.

I always turn mine off first thing, I will probably get it defaulted to off at first service.

Hope they sort your issue with it.

[DV52]

Update, after leaving my car there for a day, vw could not find any issues. Battery was tested, all firmware is up to date.

Funny thing was it did not happen all all on the way to the dealer or a few days afterwards. However it did happen once yesterday. I will leave it until it gets worst.

firstvw:Hi.
the next time that SS goes pear-shaped, why not have a look at the car's self reporting screen? Not sure if you are aware of this facility, but the discover media/pro has a screen that is dedicated to telling the driver why SS won't work. I wrote a post earier in this thread describing how to access the screen. You can find the post HERE.

if you take a photo of the screen when next you have a problem with SS, you will have a good piece of information for the dealer when you go back for another visit

Don

[DV52]

I will probably get it defaulted to off at first service.

Imolator: Hi.
I will be delighted to be proven wrong, but I suspect that your friendly dealer service manager will not be able to set up SS to default to off. In fact, I doubt that your friendly dealer service manager will agree to change the factory settings for SS in any way - at all. This has been my experience with a number of friendly dealer service managers in regards to SS.
In the end, I dealt with the problem by buying a VCDS cable and doing the fix myself. It was one of my earliest tweaks - best change that I have made to the car! My mk7 doesn't default to off, I have disabled SS entirely from the vehicle.
Don

[Imolator]

Imolator: Hi.
I will be delighted to be proven wrong, but I suspect that your friendly dealer service manager will not be able to set up SS to default to off. In fact, I doubt that your friendly dealer service manager will agree to change the factory settings for SS in any way - at all. This has been my experience with a number of friendly dealer service managers in regards to SS.
In the end, I dealt with the problem by buying a VCDS cable and doing the fix myself. It was one of my earliest tweaks - best change that I have made to the car! My mk7 doesn't default to off, I have disabled SS entirely from the vehicle.
Don

If that is the case I will have to get a VCDS cable and do it myself. Thanks for the info!