I just picked up my 2026 GLC. It doesn't shutdown very often with auto stop/start on. Ive driven 250 or so miles. Is this normal? Thx

 

There are certain prerequisites for the system to work that are described in your OM. Among these is the engine being up to normal operating temperature and the starter battery having sufficient charge. If your car was sitting on a dealer lot for several weeks, its battery charge might be low. You might want to acquire a trickle charger and see if bringing up the battery charge level remedies the issue.

 

My 2025 shuts down quite often. Thing is, unless I'm watching the RPM gauge, I don't notice it that much. It is very smooth and quiet for a stop/start system. I still turn it off from time to time when I want full control. Maybe let the batteries charge up a bit more.

 

You can check the battery level in the app.

There have been problems with charging but maybe with the 26 it’s been corrected. My 23 battery lasted 2.5 years and dealership replaced under warranty. My 26 is a PHEV and as I understand it gets topped of every time I charge. I wouldn’t worry about the auto start stop it’s pretty “automatic” and you don’t even know it’s happening after a while. If these cars were standard shift then it can be a pain. I have driven a lot in the EU and always turn it off with standard shift.

 

MB owners manuals are written by folks who believe nobody ever reads them, so content doesn't matter. My G550 OM is quite non-descript about auto start/stop. Here's what my X7 says about its auto start/stop:
Functional limitations
The engine is not switched off automatically in
the following situations:
▷ In case of a steep downhill grade.
▷ Brake not engaged strongly enough.
▷ The outside temperature is high and automatic
climate control is running.
▷ The car's interior has not yet been heated
or cooled to the required level.
▷ Where there is a risk of window condensation
when the automatic climate control is
switched on.
▷ Engine or other parts not at operating temperature.
▷ Engine cooling is required.
▷ The wheels are at a sharp angle or the
steering wheel is being turned.
▷ Vehicle battery is heavily discharged.
▷ At higher elevations.
▷ Hood is unlocked.
▷ Hill Descent Control is activated.
▷ The Automatic Parking Assistant is activated.
▷ Stop-and-go traffic.
▷ Selector lever position in N or R.
▷ After driving in reverse.
▷ Use of fuel with high ethanol content.

I can't say that all these apply to MB, but there are some that probably do. One that's not mentioned that I think applies to my G550 is if you're stopped with the turn signal active. This prevents the car from shutting off so that you're not inhibited from making a quick turn in front of on-coming traffic.