When i drive my C43 in individual mode with reduced engine and let off the throttle it will go into glide mode with the drive icon replaced with a blue sailboat icon. Sometimes when i depress the throttle again the transmission doesn't re-engage, my engine RPM shoots up as if i was revving in neutral and the sailboat drive icon stay on instead of switching back to the purple Individual drive icon. Surprisingly no error message shows up on my digital dash screen and I would just need to pull over to the side, turn the car off and back on again to fix the issue. This has happened 4 times now all of which happened on the hwy. The interval between each incident is also becoming more frequent from a couple months to a couple days. Anyone here able to shed a light on what could be the issue? I've brought the car into the dealership once already and they were not able to conclusively determine the issue and just software updated my TCU.

I’m experiencing the same problem with my 2020 E53. I either pull over to the side and shut off the car, then turn it back on, as you suggested or apply medium- hard pressure on the brake. I’m not sure what causes it.

Deactivate with a paddle. Though if there is no deactivation by the accelerator, it may be malfunctioning.

Glide mode function

With an anticipatory driving style, Glide mode helps you to reduce fuel consumption.

Glide mode is characterised by the following:

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  • The combustion engine is disconnected from the drivetrain and continues to run in neutral.
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  • The transmission position displayis shown in green.

Glide mode is activated if the following conditions are met:

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  • Drive programis selected.
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  • The speed is within a suitable range.
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  • The road's course is suitable, e.g. no steep uphill or downhill inclines or tight bends.
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  • There is no trailer hitched up to the trailer hitch, and no bicycle rack Fitted.
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  • You do not depress the accelerator or brake pedal (except for light brake applications).

Glide mode can also be activated if you have selected the "Eco" setting for the drive in the drive program.

Glide mode is deactivated again if one of the conditions is no longer met.

Vehicles with Active Distance Assist DISTRONIC:when Active Distance Assist DISTRONIC is active, the glide mode function is not available.

Glide mode can also be prevented by the following parameters:

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  • Incline
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  • Downhill gradient
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  • Temperature
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  • Height
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  • Speed
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  • Operating status of the engine
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  • Traffic situation

• Glide mode can be ended by pressing a steering wheel gearshift paddle

When the issue happens glide mode doesn't deactivate with paddles, throttle, brakes, turning ECO off or changing drive modes. The car is stuck in glide mode and giving it throttle just spikes the rpm as if it was in neutral (which it technically is). The only things that "fixes" it is pulling over to the side and restarting the car which is not always feasible depending on the road or traffic.

I've had the car at a dealership for a month and they could not diagnose the issue and returned it after doing some software updates. The dealership opened a case with MB thats still pending but i've received no updated since.

Does med-hard braking always get you back in gear when this happens? So far ive had to pull over to the side every time.

Scary...I use glide mode all the time ..I manipulate the throttle to activate glide all the time n try to coast as long as possible once it's gliding. Maybe I shouldn't use it anymore....sheesh.

It sounds like your C43 might be experiencing an issue with the Transmission Control Unit (TCU) or the drive mode logic system, especially if the problem persists even after a software update. The glide mode function is designed to improve fuel economy by disengaging the engine from the drivetrain under certain conditions. However, if the transmission isn't re-engaging properly when you press the throttle, there could be a glitch in the TCU, or possibly a fault in the sensors that monitor throttle position or gear engagement. It's also possible that there might be an intermittent communication issue between the TCU and the rest of the vehicle's control systems, which doesn't trigger a clear diagnostic error but still affects operation.
For further investigation, I recommend checking the TCU and Powertrain Control Module (PCM) for any hidden fault codes that might not display as a direct warning, especially given the intermittent nature of the issue. A full system scan with a capable tool like the youcanic is essential as it can dive into various subsystems and reveal subtle anomalies that a basic OBD2 scanner like the Innova 3100RS would miss. Have you checked if this happens consistently in specific conditions, like certain RPM ranges or throttle positions, which you might not have reported yet? Recognizing a pattern could help narrow down the problematic component.

sent you a DM - I’m having the same issue and taking the car in tomorrow. Let’s make a group case. @foomps @PHB

I left my car at the dealership for 1month+, the dealership opened a case with MB and had their engineers analyze my car data. The service advisor said they updated the TCU firmware and i've been driving in ECO mode for almost 2months now with no issues. Not sure if they did anything else though but apparently my case with MB is still open and probably being used as a reference.

Tried to DM you but it’s unavailable - can you DM me on IG directly? Handle: princealadeen_fleet

You should reach out to @BenzNinja who may be able to help. Best to go to www.benzninja.com.

Has anyone gotten any information on this issue? I have a 2022 C43 with pretty much the same exact issue. The dealership couldn't find any fault codes and said my TCU is completely up to date, so I'm not sure if there's anything else that can be done.

are the factory trained experts suggesting you should trade up??

One small detail is really disturbing this TCU...

How can MB dealer experts be so clueless ???

Seems a little too common for my liking.