Need a small favour from anyone using Auto Stop Start!

Technical Forum for the Porsche Macan
Greglambert
Posts: 8
Joined: Mon Nov 01, 2021 6:34 am

Post by Greglambert »

I'm trying to get to the bottom of why the Auto Stop Start is not working on my 2017 Macan GTS so I'm after a small favour!

Would anyone who is actively using the A/S/S functionality be able to check their battery voltage reading from the drivers multi function display, if you have it selected of course? ;)

Mine has never worked since I bought the car last October and, despite a recent 350 mile drive, the voltage still reads below 12v first thing in the morning and the A/S/S won't work (I know there's a list of conditions which prevent the A/S/S from working but I'm not using any of them, e.g. PSM, Sports mode, air con, heated seats/steering wheel, etc..etc..).

In normal driving mode the voltage reading on the display shows the alternator is charging at a healthy 14.5/15v, so on that basis I presume the alternator is ok. However, this is not reflected in the voltage reading when I get in the car the following day, as it never reads anything above 12v. Put simply, there's never sufficient voltage in the battery for the A/S/S to function (and the battery has been replaced by Porsche by the way).

I am therefore intrigued to know what other owners are seeing on the voltage readout and if their A/S/S is working ok. If others are seeing a minimum 12.5v upwards and A/S/S working I'll at least have something to go back to the dealer with!

Thanks in advance.

Toddie
Posts: 463
Joined: Thu Jan 16, 2020 2:45 pm

Post by Toddie »

I personally would consider your issue to be a bonus! it saves switching off the auto/stop start when you get in the car! I had a similar issue with my car, until I had a hip replacement operation and couldn't drive for 6 weeks, so the car spent 4 weeks or so on my ctek charger to maintain the battery, and after that the auto stop/start has annoyingly worked ever since!
2017 Macan S, Carrara White Metallic, Agate Grey Leather, 21” 911 Turbo Design wheels.
Greglambert
Posts: 8
Joined: Mon Nov 01, 2021 6:34 am

Post by Greglambert »

Hi Toddie

Appreciate Auto/Start/Stop isn't for everyone, but as an aside, I'm also concerned that the battery isn't charging properly anyway and this may lead to other electrical/starting problems further down the line.
Toddie
Posts: 463
Joined: Thu Jan 16, 2020 2:45 pm

Post by Toddie »

Hi Greg,

Just got in my car and on turning the ignition on it reads 12.2 volt, on starting the car it rises to 14.0 volts, which rises higher when under way. Just because Porsche fitted a new battery doesn't mean it was fully charged, although after a 350 mile drive you would imagine it was. As I said I had a similar issue, until I fully charged/conditioned my battery on my CTEK MX5 charger. Hope this is of some help.
2017 Macan S, Carrara White Metallic, Agate Grey Leather, 21” 911 Turbo Design wheels.
Deleted User 4752

Post by Deleted User 4752 »

Lots of Porsche owners ( none here I’m sure ) use their cars as lawn ornaments and drive them only very occasionally, presumably because they worry about service costs or residuals. Cars with auto-stop use special batteries, and if you haven’t driven it for a while they can have a funny turn. My son’s car did the same thing during the 1st year of Covid lockdowns, although that actually showed up as a battery fault. I suggest 3 things.

1, check it’s definitely the correct battery for a car with start-stop ( they are different batteries and usually a lot more expensive ).

2. Take it for a long drive ( this resolved the issue on my son’s car )

3. As others have suggested get a Ctek charger and give it a good long charge.

If all that fails, take it back to the OPC.
Greglambert
Posts: 8
Joined: Mon Nov 01, 2021 6:34 am

Post by Greglambert »

Hi Toddie, many thanks for checking that, much appreciated. Your voltage seems a little low too, but I'm obviously not familiar with your recent driving history, and the increase to 14v when starting is normal. Porsche did charge the battery fully when they swapped it and the A/S/S worked for a day (voltage read 12.8 when I collected the car) then the voltage dropped under 12v the following day and it stopped working.

Looks like it's going back to the dealership, maybe when the warmer months are here so that they can't blame the cold weather for the A/S/S not working 8-) :lol:

Thanks again
Greglambert
Posts: 8
Joined: Mon Nov 01, 2021 6:34 am

Post by Greglambert »

THHGTTG wrote: Thu Feb 17, 2022 1:51 pm Lots of Porsche owners ( none here I’m sure ) use their cars as lawn ornaments and drive them only very occasionally, presumably because they worry about service costs or residuals. Cars with auto-stop use special batteries, and if you haven’t driven it for a while they can have a funny turn. My son’s car did the same thing during the 1st year of Covid lockdowns, although that actually showed up as a battery fault. I suggest 3 things.

1, check it’s definitely the correct battery for a car with start-stop ( they are different batteries and usually a lot more expensive ).

2. Take it for a long drive ( this resolved the issue on my son’s car )

3. As others have suggested get a Ctek charger and give it a good long charge.

If all that fails, take it back to the OPC.
Hi THHGTTG

It is the correct battery, Porsche replaced the original as a gesture of goodwill, even though it wasn't covered under warranty. The car gets used regularly and, as I said in my post, we did a 350 mile trip and the battery still wasn't charged enough for the ASS to work the following day, despite the voltage readout showing 15v alternator charging during the 350 mile journey. I've tried the CTEK too, no joy there either!

As you say, back to the OPC!
Bluesnose1812
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Post by Bluesnose1812 »

Excuse me for saying the obvious - but have you checked the 2 fuses? Rear fuse box carrier C
Fuse 3 and 4
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Percymon
Posts: 518
Joined: Mon Sep 20, 2021 11:41 am

Post by Percymon »

A replacement battery needs to be coded to the vehicle, otherwise it still thinks the old battery and battery condition are present - i would have hoped the OPC knew that and coded it correctly. Batteries arrive at the OPC uncharged and in a dry state, they have to fill them and charge them, it may not have been 100% charged when they fitted it.

After a 350 mile drive it should be fully charged, unless you had a lot of electrical consumers on (lights, wipers, heated seats etc). Even so, with a healthy 14.5volt alternator output the battery should be getting some replenishment even in extreme load conditions. If you have a dashcam then they can draw power overnight too.

I put my SD on a CTEK charger from time to time, and it always manages to top up the battery level - when done , the ASS always works for several days, some journeys in slow traffic it can activate tens of times. After a few days it generally doesnt work, but i think my dashcam draws some power when parked as a result of the facility to record any bumps or movement of the vehicle.
Deleted User 4752

Post by Deleted User 4752 »

Greglambert wrote: Thu Feb 17, 2022 1:59 pm
THHGTTG wrote: Thu Feb 17, 2022 1:51 pm Lots of Porsche owners ( none here I’m sure ) use their cars as lawn ornaments and drive them only very occasionally, presumably because they worry about service costs or residuals. Cars with auto-stop use special batteries, and if you haven’t driven it for a while they can have a funny turn. My son’s car did the same thing during the 1st year of Covid lockdowns, although that actually showed up as a battery fault. I suggest 3 things.

1, check it’s definitely the correct battery for a car with start-stop ( they are different batteries and usually a lot more expensive ).

2. Take it for a long drive ( this resolved the issue on my son’s car )

3. As others have suggested get a Ctek charger and give it a good long charge.

If all that fails, take it back to the OPC.
Hi THHGTTG

It is the correct battery, Porsche replaced the original as a gesture of goodwill, even though it wasn't covered under warranty. The car gets used regularly and, as I said in my post, we did a 350 mile trip and the battery still wasn't charged enough for the ASS to work the following day, despite the voltage readout showing 15v alternator charging during the 350 mile journey. I've tried the CTEK too, no joy there either!

As you say, back to the OPC!
If they already replaced it ( sorry, i really should read the whole post before replying ) presumably the problem was around before the replacement, so definitely back to the OPC. Even if its a fuse issue, as mentioned above, may as well get the opc to do it.

For reference the ASS on the macan is the most aggressive of any car I’ve owned. It really does turn off at every possible opportunity. The scary bit is the power steering drops out as soon as the engine stops, so if you are going round a corner and stop in traffic the PS goes away with the steering on lock. Its not a big issue but it just catches you by surprise occasionally.

Unlike other though, I never “technically” turn it off. That’s because I mainly drive in sport with comfort suspension settings, which automatically disables it.
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