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Discussion Starter #1
Hey Guys,

First Issue:
I got a quick question to see if this has ever happened to anyone.
Last week, I got to work and couldn't lock my door with my key or buttons on the handle. So I replaced the batteries and it worked.

Aren't I supposed to get a low battery warning or something?


Second issue:

After replacing the batteries, everything was fine. I usually get a "key not recognized" every now and then so I guessed it was normal except today I was sitting in traffic and got a "key not recognized" so i went on driving and about 15 mins later my entire car shut off without warning (thank god i was in traffic and at a complete stop) So I had to pull my key out of my pocket, put the car in park and start the car with the key in the ignition.

Now Im afraid to use the "keyless GO" feature. What if this happened, and i was going 60mph.

Anyone ever have this issue? Any input would be greatly appreciated.


Thanks,
MrAMG55
 

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2006 CLK 350
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Well, only thing I can guess is that the new batteries were not fresh... check it with a battery tester under load. Some batteries are not new because of sitting around on the store shelf. The key does require a pretty high voltage so maybe try a different brand of batteries too?

You can always put the key into the ignition switch and turn on the car without the keyless-GO.

Does your spare key do the same thing?

:)
 

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Discussion Starter #3
Batteries were brand new....but they were sitting for a few years lol. Maybe that could be the problem and I don't have a spare key unfortunately.
 

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2004 CLK 240 Coupe
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Regarding monitoring the battery state, is there not an LED on your remote, as we have on the non keyless-GO keys?

I recommend you get yourself a spare key asap, especially with this condition happening. :)
 

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WEAK CR2025 batteries are 2.73VDC each for Keyless-GO

OK, you are right as there is a small RED led near the left side of the nose of the key that will blink a RED light when any of the buttons are depressed.

I just got the message that the key was not detected and the LED did not blink when any of the keys were pressed.

I took out the old batteries and measured the voltage at 2.73 Volts DC instead of 3.05VDC when brand new.

After replacing both batteries (CR2025) the LED will blink RED when any of the buttons are depressed.

So I think your batteries are weak (2.73V) go buy another pair of fresh CR2025's and try it again. Be sure to insert the batteries with the correct polarity... if still no blinking, then reverse the batteries. They are stacked together in series to make 6.0VDC when correctly installed.

AND YES, get a spare key ASAP before you drop the key and it stops working!

You should be able to get the new Chrome key from the dealer.

Goodluck... :)
 

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2004 CLK 240 Coupe
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11,377 Posts
unitfreebie...

On this topic of Keyless-GO, would you say that the feature is worth having?

I had no idea of the added complexity of the system until I looked through the WIS and discovered that you have 3 additional antennas and 4 additional control modules located around the car.

Additionally, following the schematic below, the number of components involved is considerable, so fault finding here will be quite difficult for the OP...

Personally I am pleased NOT to have it! :)
 

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Discussion Starter #7
OK, you are right as there is a small RED led near the left side of the nose of the key that will blink a RED light when any of the buttons are depressed.

I just got the message that the key was not detected and the LED did not blink when any of the keys were pressed.

I took out the old batteries and measured the voltage at 2.73 Volts DC instead of 3.05VDC when brand new.

After replacing both batteries (CR2025) the LED will blink RED when any of the buttons are depressed.

So I think your batteries are weak (2.73V) go buy another pair of fresh CR2025's and try it again. Be sure to insert the batteries with the correct polarity... if still no blinking, then reverse the batteries. They are stacked together in series to make 6.0VDC when correctly installed.

AND YES, get a spare key ASAP before you drop the key and it stops working!

You should be able to get the new Chrome key from the dealer.

Goodluck... :)

I just changed my batteries to some fresh Sony Cr2025 (170 mAh each). The red LED does come on when the button is pressed. But, now im afraid to drive on keyless GO since that happened lol. I might bring it to the dealer just in case. It just blows they charge a $150 diagnostic fee.
 

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Yes the KeylessGO is worth having for the convenience of not fumbling around for the keys, at least when it does work! If it stops working due to a low battery or malfunction, then just plug the key into the ignition and use it like any other Smartkey.

Well, I guess it is more of a convenience for my wife since they generally carry the key in their purse and not in the pocket like us guys.... :)

One of the features of the KeylessGO is that the car engine will shut off after a while if the key is not inside the car, which is to prevent a thief from driving very far if the engine was left running and the key was in the owner's pocket.

So if the RED led light on the Keyless-GO smartkey did not work before you changed the batteries, then that was the reason the engine shut off after a period of time. If the RED led now blinks brightly when the buttons are pushed, then I would say you are OK to go.... of course, you can always have the dealer run the diagnostic if you want to have peace of mind.

I am not sure about the full 170 maH current measurement as that can drain down a good battery but the way I check batteries is under a load tester (20 mA load drain) then measure the battery voltage to see if the battery will read 3.00 VDC for 5 seconds. If the battery tester reads 2.75VDC, then the battery is no good for Keyless-GO usage, but you can save the battery for use in other applications like a pocket LED light!

By the way, using a high impedance voltmeter or DVM to measure the open terminals of the 3V lithium ion battery WITHOUT a test load is NOT a valid test for batteries to be used in the Keyless-Go Smartkey.
 
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