Is ECO start/stop function watching the traffic lights?
Thread Starter
Super Member
Joined: Oct 2014
Posts: 787
Likes: 110
From: BNE, Australia
W205 C250BT
Is ECO start/stop function watching the traffic lights?
Here's a question for other owners - I've had the car for nigh on six months now and would say I'm fairly used to the behavior of the various automated smart bits. One thing keeps nagging me though... I'm wondering whether the car is keeping a look out for certain events other than the usual collision avoidance scan? More specifically I'm starting to think the car is watching the traffic lights.
When you pull up at a set of red lights and the ECO start/stop feature kills the engine, I've found that quite often the motor comes back on the same instance that the lights go green. I know what you're thinking - you're just lifting the brake slightly, but no. I've had this happen whilst I'm in the HOLD mode not even touching the throttle or brake and even when 2 or 3 cars back from the light.
I know the car fires up if you're on auto-cruise, stopped in a traffic jam and then the car in front moves away (with driver assistance plus), so there's definitely some code which links the forward camera to the start/stop, but I've never read anything which indicates that it monitors traffic lights.
First few times I thought it may just be random coincidence, since the car fires up at various times anyway when on start/stop to refresh the aircon etc. It's just happened way too many times to be coincidental I think.
Anyone else experience or notice a similar pattern?
When you pull up at a set of red lights and the ECO start/stop feature kills the engine, I've found that quite often the motor comes back on the same instance that the lights go green. I know what you're thinking - you're just lifting the brake slightly, but no. I've had this happen whilst I'm in the HOLD mode not even touching the throttle or brake and even when 2 or 3 cars back from the light.
I know the car fires up if you're on auto-cruise, stopped in a traffic jam and then the car in front moves away (with driver assistance plus), so there's definitely some code which links the forward camera to the start/stop, but I've never read anything which indicates that it monitors traffic lights.
First few times I thought it may just be random coincidence, since the car fires up at various times anyway when on start/stop to refresh the aircon etc. It's just happened way too many times to be coincidental I think.
Anyone else experience or notice a similar pattern?
Junior Member
Joined: Mar 2015
Posts: 48
Likes: 3
From: East Coast, USA
2015 C300 4MATIC
Not at all. Like Lego said, it is the most annoying thing about the car (just my opinion) and it does not watch for any events. Just that the car might have required more power and the engine was switched on just as the traffic light changed green. It would have been pure coincidence.
Senior Member
Joined: Apr 2011
Posts: 250
Likes: 14
From: Longueuil, QC Canada
2018 E300 4Matic.
My A/C compressor will not restart engine.
When the engine stops on a red light in my 2015 C300, it will not restart for the A/C. Car just gets warmer and warmer until the engine starts when I let go of the brake pedal or touch the accelerator.
Is this normal?
Is this normal?
Newbie
Joined: Jul 2015
Posts: 10
Likes: 1
From: Irving, TX
2015 Mercedes C300
This is how it works:
If you are not using climate control, it'll never turn on automatically. Will remain dead until you press the gas pedal
If you are using climate control, then the car turns the engine on when cabin temperature rises above your set comfort level. It's the car's computer that decides when to turn on and merely a coincidence that the signal turned green at that time.
It may happen that the start-stop won't kill the engine at all if the cabin temperature is too high.
It happens to me all the time. Hope this helps
If you are not using climate control, it'll never turn on automatically. Will remain dead until you press the gas pedal
If you are using climate control, then the car turns the engine on when cabin temperature rises above your set comfort level. It's the car's computer that decides when to turn on and merely a coincidence that the signal turned green at that time.
It may happen that the start-stop won't kill the engine at all if the cabin temperature is too high.
It happens to me all the time. Hope this helps
Last edited by adakshi; Sep 11, 2015 at 08:33 PM. Reason: correction
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Senior Member
Joined: Apr 2011
Posts: 250
Likes: 14
From: Longueuil, QC Canada
2018 E300 4Matic.
My C300 will not restart if it needs A/C.
My C300 will not restart if it needs A/C ... nor would the CLA250 I was lent while my car was in the shop for annual service, this week.
This is how it works:
If you are not using climate control, it'll never turn on automatically. Will remain dead until you press the gas pedal
If you are using climate control, then the car turns the engine on when cabin temperature rises above your set comfort level. It's the car's computer that decides when to turn on and merely a coincidence that the signal turned green at that time.
It may happen that the start-stop won't kill the engine at all if the cabin temperature is too high.
It happens to me all the time. Hope this helps
If you are not using climate control, it'll never turn on automatically. Will remain dead until you press the gas pedal
If you are using climate control, then the car turns the engine on when cabin temperature rises above your set comfort level. It's the car's computer that decides when to turn on and merely a coincidence that the signal turned green at that time.
It may happen that the start-stop won't kill the engine at all if the cabin temperature is too high.
It happens to me all the time. Hope this helps
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Super Member
Joined: Mar 2002
Posts: 664
Likes: 33
From: Ft. Lauderdale
2015 C300, 2025 GLC300 4Matic
Then it must be defective. That is why I don't use it here in Florida. It is always hot, so it won't stay off for more than 10 or 15 seconds.
MBWorld Fanatic!
Joined: Jun 2008
Posts: 2,073
Likes: 85
From: San Francisco, CA
2017 E300
I wouldn't go as far as to safe defective. Is it because of ECO vs Normal modes? I would think in ECO mode, it will let the ambient air temp get warmer and not restart the engine. In normal, I would think it would restart the engine to give you more comfort instead
Senior Member
Joined: Jun 2015
Posts: 337
Likes: 7
From: North San Diego, CA
2015 C300
this is correct, at least from what i have gathered
Senior Member
Joined: Apr 2011
Posts: 250
Likes: 14
From: Longueuil, QC Canada
2018 E300 4Matic.
Newbie
Joined: Jan 2014
Posts: 1
Likes: 0
GL450
One issue is that it drains the AUX battery. Ironically, when the AUX battery drains ECO start/stop disables along with several other functions i.e. distronic plus. Does anyone know which specific fuse would disable the ECO start/stop and if the fuse is removed will that disable any other functions?
