KINGSRULE

2018 Panny 4s

Other than putting car in Sport Mode, can auto start/stop be permanently turned off?
And if so, is it done by the dealer or an aftermarket solution?

TU

K

pokingaround

To my knowledge no one has been able to permanently turn it off. However, if you'd rather not put it into Sport mode, you could make 'Off' part of your Individual mode.

KINGSRULE

Thank you but I should have clarified I don't want to press any button when I start the car to have auto s/s off


From what i can gather with the Porsche PIWIS u can program auto s/s:

Always ON
Always OFF
Remember last setting

But I haven't confirmed that it has/can be done on US cars....

pokingaround

I believe the collective wisdom is that it cannot be done on US cars. An EPA thing. But, I'm not positive whether it's been tried.

Surfingjeff

I don’t think it’s even epa my Bmw has a switch .to shut down the auto off on

malrash

I’ve saved settings in individual mode. All I have to do is rotate the dial on start up. No other way out

Robuk

There is, try disconnecting the sensor attached to the negative lead of the starter battery.

PorscheGuide

Only company I've seen that can stop it (sadly not on a Porsche) https://www.autostopeliminator.com/

Robuk

Disconnecting the battery sensor is no different to it failing, If the the EMU can`t read the SOC of the battery it will not engage stop/start and will go into a pre-determined default charging mode so no smart charging or regeneration, the fuel savings from these two systems is minimal anyway and should not bother anyone who can afford a Porsche with this system fitted. Other than a small saving on fuel perhaps someone can post any other benefits this complex system may provide.

lewis.s

Two items

Car makers are mandated to have certain fuel efficiencies across their fleet (C.A.F.E.) Every little bit helps which is why they have this annoying start / stop. If you can disable it permanently the EPA does not count the pickup they get from start/stop towards the fuel efficiencies.

100% you can not permanently disable the Porsche auto start / stop in any "normal" way

I agree its annoying

krabman

The EPA requires that cars that have multiple modes which may effect engine programming, shifting algorithms, start/stop, or any other feature that may alter emissions and economy on the certification testing have those cars default to the mode that was used for certification at every start unless no specific mode was used and the car can attain the result in any mode. BMW showed the EPA evidence that owners were routinely and regularly turning off start/stop in a petition to allow the feature to be disabled and were granted that petition. This allowed dealerships to do so but only at the request of the owners after the new car sale. Most of you probably know that the testing cycles are not done on the road, the entire procedure is performed on a dyno and usually by the OEM itself with about 15% of new cars actually being tested by the EPA. Start/stop itself is not greatly beneficial in real world driving and may even hurt economy in some cases with it's unrealistic benefit in the testing results due to "industry input" in the process of designing the tests.

The start stop is sometimes actuated by a lead to the brake lights or brake pedal which tells the controller the brakes are on, this information along with the car being in drive when all other conditions are met will initiate the engine shut down. This process can be short-circuited by pulling the lead at one of those locations. This is how you disable it on a late model Jaguar as an example, pull a lead on the passenger side brake light.

Robuk

Stop/start will not activate if the EMU believes the SOC of the battery is not of an adequate level to enable the battery to restart the car, without the sensor in play stop start will not be activated, certainly in Mercedes with this sensor disconnected stop start will not activate. The Mercedes SLK55 has an 8 cylinder engine, (see SLK forum post by Col) a faulty Battery sensor caused Col to loose stop start and cylinder deactivation, he changed batteries and even repaired the sensor supply wires, still no go, it was only when sensor was replaced everything worked. Col wanted to get rid of stop start but retain cylinder deactivation, having read my posts he decided instead of disconnecting the sensor he would break the sensor signal wire and insert a switch into the circuit, he now has a switch inside the car which disables stop start but does not affect cylinder deactivation, he feels more comfortable with the switch in play sooner than disconnecting sensor. If this disconnect works on Merc`s it surely must work on Porsche`s unless they have a totally different way of checking the state of charge of the starter battery.

lakeviking

There is an after-market solution, and it's different than the one mentioned a few posts above. I've ordered one for my 2019 911 that is coming in. I'm at an airport and don't have the company name handy, but I'll try to remember to post it later, or you can pm me. They have an online instructional video; seems pretty easy. I've also seen this company mentioned on other similar threads, though it might have been for 911s and not Panameras.

Robuk

The thing is, it is not just stop start that is an issue, the system is also linked to energy regeneration, to make this work there has to be room within the battery for a fast (15-16volt) intermittent charge from braking and coasting, this means that the EMU controlled alternator will not put energy into the battery under the cars engine power if the batteries SOC is above 75%, the other 25% is for regeneration only, this is intermittent energy and depending how the car is driven may not happen to any extent, in that case the battery could remain under charged for long periods and fail early. As the driver does not know the actual SOC he/she may as an example leave the car at an airport for a week or so and on return find the battery is flat, even if the driver knew the SOC what could be done about it. By disconnecting the sensor the EMU reverts to a pre installed continuous charging regime (it does in the Merc) which means the alternator will charge continuously at between 13.8 and 14.3/4 volts as was the case in my now sold Porsche Boxster gen2. With the old system the alternator always attempted to keep the battery fully charged, the smart system attempts to keep the battery at 75%. For a small gain in fuel it appears there are some reliability issues, me, I prefer to always have a fully charged battery and NO stop start.

krabman

That's why the brakes are the way to go if possible, the car will never attain a stop condition but it has no effect on anything else.