Keyless go - does the key need to be in the car to drive?

[sakauk]

Hi,
I got the new C class (W205) and its got the keyless go feature. If i dont have the keyfob in the near range it wouldn't start, but the other day I started the car and while engine running (to defrost) I walked in to the house to get some stuff but actually realised the key is still in my pocket and the car hadn't stopped. I was about 15 meters away and in the house I was amidst brick walls etc. So definitely I was out of range.

Does it mean that once started someone can drive off without the keys?

Thanks
Sak

 

[daveenty]

Yes. Once started the key isn't needed, so theoretically anyone could drive it away if the engine is running.

Once stopped however they're not going to start it again.

 

[sakauk]

Thanks for the quick reply.

Do you think this is how all keyless gos work - or is just Mercedes thing ?

Just that it seems a bit daft design to me, i mean, me and my wife both drive this car and i could see one of us one day driving off while the key is in the others pocket only to be stranded with no key to start the return journey!.

Cheers
Sak

Yes. Once started the key isn't needed, so theoretically anyone could drive it away if the engine is running.

Once stopped however they're not going to start it again.

 

[gl boy]

An mesage will come up and the annoying bleep will activate when the key is out of range . Slight fail safe system and then you know the keys not with you !!

 

[DSM10000]

Thanks for the quick reply.

Do you think this is how all keyless gos work - or is just Mercedes thing ?

Just that it seems a bit daft design to me, i mean, me and my wife both drive this car and i could see one of us one day driving off while the key is in the others pocket only to be stranded with no key to start the return journey!.

Cheers
Sak

Surely you just make sure you have the key before you drive off?

It seems a little unfair to criticise Mercedes for designing a feature that you (presumably) find useful that just needs the normal input from the driver.

 

[ShaunB]

Thanks for the quick reply.

Do you think this is how all keyless gos work - or is just Mercedes thing ?

Just that it seems a bit daft design to me, i mean, me and my wife both drive this car and i could see one of us one day driving off while the key is in the others pocket only to be stranded with no key to start the return journey!.

Cheers
Sak

Thats how it worked on a previous car of mine (330S Impreza)
You needed the key firstly to gain entry, and then to start the car.
If you moved away from the vehicle while it was running, it beeped to warn you

 

[Spin_bowler]

Thanks for the quick reply.

Do you think this is how all keyless gos work - or is just Mercedes thing ?

Just that it seems a bit daft design to me, i mean, me and my wife both drive this car and i could see one of us one day driving off while the key is in the others pocket only to be stranded with no key to start the return journey!.

Cheers
Sak

My old Mondeo used to work in exactly the same way. I only managed to complete a journey without it in the car once. Fortunately, my first stop was to drop the kids off at Nursery so it only involved a mile on shank's pony rather than being stranded in my final destination (250 miles away in Devon).

 

[ManiacGT]

Equally if the system stopped the car because it couldn't find the key any longer. What would happen if the key suffered radio interference or its battery died. You'd screech to a halt at a random point, not that safe really. Best just to remember to keep your key with you when you use the car. Something you should do anyhow if prior cars had normal (non KG) keys.

 

[AMGeed]

Equally if the system stopped the car because it couldn't find the key any longer. What would happen if the key suffered radio interference or its battery died. You'd screech to a halt at a random point, not that safe really. Best just to remember to keep your key with you when you use the car. Something you should do anyhow if prior cars had normal (non KG) keys.

That isn't how Keyless Go works. Once the car has been started, the key is irrelevant. If the key did decide to die,the engine would not stop and nor would you "screech to a halt at a random point". To stop the engine you press the button on the gearstick.

As an aside, on my model, putting the key into the EIS disengages the button on the stick and you cannot start the car on the button. You have to use the key in the EIS.

 

[markmifsud]

So what would happen if you was standing next to your car, thus enabling the system and some toerag decided to make off with your car?

 

[daveenty]

So what would happen if you was standing next to your car, thus enabling the system and some toerag decided to make off with your car?

Mine won't start unless the key is physically in the cabin.

Having said that, if the scenario you mention were to happen, I may find myself in the possession of a blunt object to curb his enthusiasm...

 

[V12]

That isn't how Keyless Go works. Once the car has been started, the key is irrelevant. If the key did decide to die,the engine would not stop and nor would you "screech to a halt at a random point". To stop the engine you press the button on the gearstick.

As an aside, on my model, putting the key into the EIS disengages the button on the stick and you cannot start the car on the button. You have to use the key in the EIS.

Have you tested that?
I tested it on my W220 and the engine will actually turn off if you don't have the key. Driving along at 30ish and the key warning came up in cluster. Then slowed down at next junction, as the car came to a standstill, the engine cut.
I presume from this that the DAS is continuously checking to make sure the key is still there etc.

It's a great system on MB. My car has 7 antennae for the system and with the capacitive touch door handles it was really head and shoulders above the competition. Recently travelled in a 14 plate discovery, dealer demonstrator with every option ticked. The keyless go wasn't as good as my old W220. No capacitive handles for a start and the range wasn't as strong.

 

[markjay]

On my other car (not MB), when the wife jumped off at the traffic light with the fob in her handbag, there was an alarm sound and the dash displayed a message 'Key not Present', but the car drove normally. I drove on and managed to catch up with Mrs MJ ten minutes later, so no idea how long the car would go without the fob.

 

[boxbrownie]

Until key off normally. They are designed so the car does not stop anywhere dangerous, level crossing etc.

Usually keyless is designed only to start when the key is inside the cabin, there are several antenna around the car to enable this, hence why on some you cannot lock the key in the trunk.
So if your outside and somebody jumps in they cannot start the car.

 

[C240Sport97]

So if your outside and somebody jumps in they cannot start the car.

on my CLS, even with the key in the driver's door lower compartment and door open, it does not start. have to close door to start

 

[AMGeed]

on my CLS, even with the key in the driver's door lower compartment and door open, it does not start. have to close door to start

Same as my E class. I guess its a safety feature that you have to depress the brake pedal before pushing the start button. Saves any youngster in the car accidentally starting the car if the key was in there too.

 

[SLKGirl]

I have Keyless Go as an option on my car, but I've turned it off and use the key...

 

[AMGeed]

I have Keyless Go as an option on my car, but I've turned it off and use the key...

Can I ask why? I wouldn't be without it now.

 

[Major774]

Warning for you Keyless Go users with the boot lid closure feature.

If the key is in the boot and you press the close boot lid only button... The boot lid will continue to close with the key still in the boot (possible to lock yourself out). However, if you press the close boot lid/central locking button with the key in the boot... The boot lid will refuse to close.

 

[C240Sport97]

If the key is in the boot and you press the close boot lid only button... The boot lid will continue to close with the key still in the boot (possible to lock yourself out).

not locked out though as you can open the boot?

having said that I once had key in the boot accidentally, and the boot would not close with either button