Stop/start not working

[graeme]

Sooo I've been sitting on this issue for quite a while now, but I think it's time to get it seen to in case I'm hurting anything else by leaving it.

My stop/start system has only activated one time within the last 4+ months, any time I have checked the stop/start section in the infotainment, I see "Power consumption is too high", twice I have seen a message along the lines of the engine not being turned on (despite it being on obviously). This happens whether or not I have things like heating on, music playing, or nothing at all.

I know the system may not activate in colder weather but the message received shouldn't be about power consumption then(?), the temperature here generally hasn't been that bad at all, plus for the amount of time this has been going on for it seems like a problem to me.

Is this something anybody has some experience with? Could a reconnect of the battery fix this or best to take it to the dealers? *shudders*

Edit: I don't own a VCDS so can't provide a scan output if that would have helped at all.

[RUM4MO]

Okay, I think that you need to take that car into your local VW dealer to check it out, but before that, if you can start from cold and run that car with the AC system switched off completely, and it is safe not to need to switch the auto lights on, I'd hope that after driving it for a mile or so, if you come to a halt, the engine get switched off by the Stop/Start system. That is easily achievable with my wife's August 2015 Polo 1.2TSI 110PS even now in deepest winter!

[EDI GTI]

From personal experience with my 2016 GTI, the cars start/stop will only turn on once the engine has reached a temperature of 90, the thing with 'The engine must be switched on' seems to be a common issue, I suspect its just a sensor in the car that mustn't always work as planned - but you aren't alone with that one. I also find that if I have the temperature of the car set at anything above 23 degrees, again the start/stop won't work.

If you are trying to activate the start/stop with the same conditions above and its still not working, then I would also recommend taking it to the dealer the same as RUM4MO.

[graeme]

Thanks guys, yeah I do a ~60 mile drive pretty frequently and even after that there's no change, dealers it is then...

[graeme]

Booked in for next week at AC, will provide an update when I have one.

[PeterWestSussex]

We (or should I say my wife) would love the problem you have. With the DSG box, safely pulling away at a roundabout or safely exiting into a busy road is not helped by an engine which first has to re-start! And the recent Daily Telegraph review of the new Polo specifically mentioned this.

Yes, there are ways to 'prep' the engine (to get it started before pulling away) but for those for whom that is too technical the general advice is "SWITCH OFF THE STOP/START every time you start the engine. Make it part of your start-up routine EVERY time.

Nevertheless, I look forward to your update once you've been to dealership's service dept.

[RUM4MO]

Hum, handing your pride and joy over to AC - ah well, needs must I suppose.

It is maybe becoming a bit clearer that too many of these cars are either suffering from a "too late" or a "too early" operating of the Stop/Start systems, I certainly have never had any issues with my wife's August 2015 Polo 1.2TSI, but as I have said, if the lights are not used and I have kept the cabin fan switched off to speed up the warming of the engine, after about a mile, starting from seriously cold but garaged, Stop/Start will be active if I get halted by traffic lights - and have forgotten to disable it - so that might place her car in the "too early" category?

Edit:- actually I should counter that "AC comment" by adding that my local "proper" SEAT dealership could not sort out my daughter's late 2009 Ibiza battery drain problems, dismissing my "there might be a s/w patch needed for the BCM" as being internet waffle/disinformation - well after being closed to be replaced by expensive housing(handy to prop up that garage group's money figures), I reluctantly booked it into my local AC SEAT - who immediately suggested that it might be a BCM S/W issue - and it was! At least they were open to the possibility that it was an old now mainly forgotten about BCM S/W issue that even the SEAT knowledge data bank could not reveal, it was only placing an unresolved incident on the main SEAT tech help thing that returned that resolution a few days later - a job well done!

[iichel]

I think that in the time I have owned my Polo Bluemotion, the start/stop system had been working most of the time. Never had an issue with it unless I messed with it...
- kessy key not present
- bcm coded badly
- some kind of dysfunction in the wiring loom
- battery state of charge too low
- something broken
- egr valve defective (arguably a vw quality issue)

The list of perquisites for start/stop is quite long
- engine temperature
- overall electrical power consumption
- climatronic settings
- brake booster pressure
- something on the towbar
- car level (flat or on an incline)
- kessy key in car
- engine healthy
- battery state of charge
- window defoggers are on (front and rear)
There are probably a few more but these apply on our polos

[graeme]

Thanks iichel, I'll go with the 'something broken' option here

[graeme]

Well, car was in for the day and it turns out my battery is faulty (but still drivable fine(?)). Batteries are back-ordered so I will get a new one fitted when they get one in.

[iichel]

that's quick for a battery to go bad

[graeme]

Yep, was pretty surprised to hear it and they didn't really give any details on what had went wrong with it. I expected it would be down to some kind of sensor failure or a reset-able error. All under warranty though so not too fussed.

[RUM4MO]

I have noticed that quite a few Skoda Fabia MK3 owners have reported batteries failing in early life, these batteries are just EFB and so not proper AGM ones that normally get used with Start/Stop, ie something a lot cheaper!

That is, if your battery has EFB written on its case along with all the other stuff!

My wife's August 2015 Polo 1.2TSI 110PS SEL switched off yesterday after I had driven it about half a mile with auto headlights off and cabin fan fully off from start - I did not expect that! I had noticed that it can do that after a mile in cold weather in the past, but half a mile!!

It does work okay is I've forgotten to disable it and am in a traffic queue where there has been a few Start/Stops, ie it will disable that function itself to prevent the battery discharging too much due to frequent engine re-starts, so in that car it can still function as intended, it is just this cold start in cold weather, along with fans off and lights off behaviour that confuses me slightly, I give it a health check every year to make sure it is not dying quickly!

[veteran]

Yes, as the other respondents have pointed out, there can be a host of quite valid reasons why Stop/Start ceases to work (either temporarily or permanently), but they all hinge around the state of the battery, I'd have thought. Even if you do 60 miles a day, insufficient charge may be going back into the battery to enable it to keep on doing stop/start. For instance, it could depend on your driving pattern (that 60 miles could conceivably be in an urban environment), or there might be other drains on the battery's capacity, eg. from an aftermarket accessory that's been fitted. There might even be a fault with the alternator's output (the alternator being the source of battery top-up charge whenever the engine's running).

I think the moral of the story is not to neglect the battery and assume that the battery management will always automatically do the right thing, but instead you yourself to regularly check the battery's state (at the very least, the quiescent on-load voltage at the battery terminals should tell you something) and provide it with a top-up. There are now a number of battery-chargers on the market that are especially designed to cope with EFB and AGM stop/start batteries, and you can use these chargers safely without needing to disconnect the battery from the vehicle's electronics. Incidentally, if you use any such charger, the latter will need to be connected not directly to the post on the negative side but instead to vehicle chassis. Unless you do this, you'll be bypassing the built-in 'resistor' at the negative terminal, preventing the battery management from assessing the net amount of charge going back into the battery at that time, and in due course this could lead to premature shutdown of stop/start and/or other current-hungry operations.

Clearly, the owner establishing whether the battery itself has now a permanent fault is more difficult than in the pre-stop/start days but nonetheless in your shoes I'd be inclined to put off a visit to the dealer unless and until it becomes totally unavoidable, as my feeling is that the dealer, in the face of any contrary evidence as to the cause, will simply take the easy way out and fit and register a new battery. The bill you'd get for that would be quite substantial, as EFL/AGM stop/start batteries are very expensive, being typically twice the cost of a conventional calcium-type lead-acid battery. Registering of the new one into the system could attract a substantial fee as well. Of course, you're going to end up with a big bill for battery replacement some day, but an EFL/AGM should certainly last for more than a year at a time if used correctly.

[SRGTD]

Clearly, the owner establishing whether the battery itself has now a permanent fault is more difficult than in the pre-stop/start days but nonetheless in your shoes I'd be inclined to put off a visit to the dealer unless and until it becomes totally unavoidable, as my feeling is that the dealer, in the face of any contrary evidence as to the cause, will simply take the easy way out and fit and register a new battery. The bill you'd get for that would be quite substantial, as EFL/AGM stop/start batteries are very expensive, being typically twice the cost of a conventional calcium-type lead-acid battery. Registering of the new one into the system could attract a substantial fee as well. Of course, you're going to end up with a big bill for battery replacement some day, but an EFL/AGM should certainly last for more than a year at a time if used correctly.

In the case of the OP, the car (and battery) are still under warranty so battery is being replaced by VW at no cost to the OP - see below;

Yep, was pretty surprised to hear it and they didn't really give any details on what had went wrong with it. I expected it would be down to some kind of sensor failure or a reset-able error. All under warranty though so not too fussed.