[Mg_m340i]

Just took US delivery of my M340i and notice that the auto stop/start "off" button is...not there anymore. Coming from a 2017 F30, I was prepared to have to disable the ASS each time I got in the car, but now it appears that button is entirely missing.

In sport mode, it still deactivates ASS. I am wondering if I can use bimmercode to also disable it in comfort mode, even though the physical button is missing. Anyone else have experience with this in a '21?

UPDATE :

Confirmed this is standard for 2021 M 340 models. Followed another users suggestion to configure Individual Sport mode with all comfort settings. This is the setting I use when I know I am going to be in stop & go traffic on my commutes.

[Burrcold]

That's so stupid.

[Benjamin_Nicholas]

Wow.

That's garbage. Glad I took the 2020.

[Mg_m340i]

Originally Posted by Benjamin_Nicholas

Wow.

That's garbage. Glad I took the 2020.

Right?! Mine was supposed to be a 2020 but ordered too close to the switch over date I guess.

[mhkorean]

There HAS to be someway to disable the ASS in comfort mode without having to code it in. No way BMW would mess that up...right?

[50M]

Originally Posted by mhkorean

There HAS to be someway to disable the ASS in comfort mode without having to code it in. No way BMW would mess that up...right?

2021 M340 is a mild hybrid, so no ASS button - hybrid drive train.

Is there a noticeable engine turn on / turn off like typical auto start stop?

[Auditobimmer42]

I read somewhere (maybe even on this forum) that it might have something to do with the 48V mild hybrid system in some of the 2021 cars. My friends X5 is also missing it

[BigWagonFan]

Originally Posted by m.b

Is there a noticeable engine turn on / turn off like typical auto start stop?

I'm really waiting for reviews on that in MHEV.

[50M]

Originally Posted by Auditobimmer42

I read somewhere (maybe even on this forum) that it might have something to do with the 48V mild hybrid system in some of the 2021 cars. My friends X5 is also missing it

Yes 2021 M340 is a mild hybrid with a 48V. The car window sticker confirms it.

[zamboni]

All new G20 after July production came with 48V mild hybrid system and BMW removed the ASS feature.

[Ikester19]

Originally Posted by zamboni

All new G20 after July production came with 48V mild hybrid system and BMW removed the ASS feature.

Interesting, I didn't know BMW was introducing MH in the G20 M340i. Glad I got my German built 2020 without the MH system

[ThatKrazyPolak]

Had a question, with that new 48V system do you feel that the moments when the engine turns itself on after idling are less jarring? Is the auto start / stop function overall less of a nuisance?

[themnmd]

Should still deactivate when in sport or sp+ mode

[rcz22]

I thought this was a good video that explains it....

https://www.youtube.com/watch?v=hvpus27PM7w

[eforty6_m3]

Originally Posted by themnmd

Should still deactivate when in sport or sp+ mode

[mfdutra]

I have the same car with the same "problem". I've coded to always start in sport individual, then I configured sport individual to be "comfort" on all items. It has solved the problem for good here.

That said, the stop/start thing on the mild hybrid is much better than in my previous 2018 540i. Also that said, I still hate it. :-D

[eforty6_m3]

Originally Posted by mfdutra

I have the same car with the same "problem". I've coded to always start in sport individual, then I configured sport individual to be "comfort" on all items. It has solved the problem for good here.

That said, the stop/start thing on the mild hybrid is much better than in my previous 2018 540i. Also that said, I still hate it. :-D

What did you use for coding? I have never had a car that really required me to dip my toes into the coding pond. But that's about to change.

[mfdutra]

I use the app Bimmercode on my Android phone, with this adapter:

https://www.amazon.com/ScanTool-OBDL...dp/B00H9S71LW/

It's quite simple and dumb proof. I've also changed my cluster and HUD to the M version, which is much nicer.

[Dw85]

I have had my 2021 for almost one month now. If the car is in sport mode the engine does not shut off.

I will say i do not notice it when it shuts off especially now that it's cooled down outside. The AC slowing down on a hot day was annoying. Other than the AC I have not noticed.

[Burrcold]

Originally Posted by Dw85

I have had my 2021 for almost one month now. If the car is in sport mode the engine does not shut off.

I will say i do not notice it when it shuts off especially now that it's cooled down outside. The AC slowing down on a hot day was annoying. Other than the AC I have not noticed.

Your AC would still slow down when the auto start/stop would engage? I thought that was the entire point of the mild hybrid (keep auxiliary things going seamlessly when it engages).

[Flamingi]

Originally Posted by Burrcold

Your AC would still slow down when the auto start/stop would engage? I thought that was the entire point of the mild hybrid (keep auxiliary things going seamlessly when it engages).

That's not the reason for the mild hybrid, in fact it probably has nothing to do with MH at all. The AC is using a vacuum to blow the air over the condenser coil and into the cabin, which is provided by the engine. In order to still have a vacuum to blow air while the engine is off, there is a vacuum reservoir. To increase the time that reservoir lasts the AC will blow less air into the cabin, once it is depleted the engine kicks back on. Also, the AC compressor is belt driven (may not be the case with modern vehicles not sure on that), so that part is not working as well when the engine is not running.

Keeping auxiliary things going is a nice bonus, but also not the main advantage of the mild hybrid system.

The starter generator is the big advantage of the 48V system. It can provide additional torque while accelerating, it turns the engine on faster and more seamlessly/more comfortable and mainly it allows the engine to turn off while moving (coasting).

If anyone wants to have some more in depth information on that topic, it was discussed in this thread already.

[stein_325i]

Originally Posted by ThatKrazyPolak

Had a question, with that new 48V system do you feel that the moments when the engine turns itself on after idling are less jarring? Is the auto start / stop function overall less of a nuisance?

One guy on the G30 forums posted his thoughts on the updated ASS functions. He basically concluded that it wasn't much of an improvement, loss in AC functionality still exists along with feeling the transition between on and off.

https://g30.bimmerpost.com/forums/sh....php?t=1759794

Originally Posted by AF

The auto start stop is just as obvious on this car as it is on mine .... not a bad thing in most cases except it still cuts down the hvac system to half. It also seemed to kick in at every stop, not at a quick stop sign stop but if you sat there for a few seconds it would go off, in my car I do not notice it kicking in as much, there are times I am at a light and mine doesn’t turn off at all, it could be the weather which was in the low 70’s so maybe the AC didn’t need to work as hard but I did notice at a light that was long the car was getting warm enough inside I put the car into sport model to Eliminate this feature. It really bothers me you can’t shut it off in comfort mode. The other thing I noticed is in comfort mode the tach changes to some type of electric gauge, i’m not quite sure what it is measuring though someone here can probably give more information. The bmw genius said it was showing the brake regenerating but that doesn’t make sense being the more I accelerated the more the electric tach went up to the higher numbers.

The part that bothers me about the auto shut off feature is it shuts down the hvac system to 1/2 which I find really noticeable, maybe all hybrids do this ... I don’t know.


As far as the hybrid part, truthfully I tried to listen to see if the engine was off at super low speeds but it seems to kick in when I hit the gas pedal from a stop just like my car, if you didn’t tell me it was a 2021 model I would not know there was an electric motor.