sdwtchlvr

I have a 2007 SL550 that I've owned for about a month or so. It just came to my attention that I can turn the radio on with no key present in the car. I have Keyless GO but none of those features really work.

-I cannot lock/unlock the car with the door handles, not sure if the handles are broken or what but I must use the key fob to lock/unlock car.

- The Start button on the gear shift does nothing. Button might be broken?

-When the car is locked and I pull on the handle, the MB logo comes up on the screen and the dash read outs come on like the mileage and what not...I thought that was weird. That happens whether or not I have the key on me.

-The 'Don't forget Key' chime always comes on any time the doors are open, whether I have a key on me or not.

Could it be that a key is hidden somewhere in the car. This all seems pretty strange to me. Any input would be awesome!

Love the car otherwise though.

Rudeney

It is normal to be able to turn on the radio without the key. This is a common feature in most all MBZs.

As for the KeylessGO system not recognizing the key: What happens when you press the start/stop button? Do you get any messages on the instrument cluster? Do you have more than one key, and if so, do both keys have this problem? Check fuse 58 - it's on the fuse panel in the storage compartment behind the passenger seat.

sdwtchlvr

Nothing happens when I press the button on the gear shift. The other day I tried it and thought I may have heard a faint sound in the engine but I'm no so sure. No messages on the instrument cluster. I had a local independent Mercedes shop look it over shortly after buying it and they didn't spend too much time diagnosing the non working Keyless Go as I didn't want to pay them specifically for that. They did put on the receipt that a new button was needed for the gear shift but I'm not sure if that was just a suggestion as to what it could be or if that's what it was for sure. They did hook it up to the SDS and only got one code for the intake manifold but nothing else.

Should I look into replacing the gear shift button and see if that's the culprit...just don't want to dump a ton of money into something that is just a convenience feature. Speaking of convenience feature, I did have to replace the Aux battery as I was getting the warning that some of my convenience features were unavailable. The Aux battery tested bad and we (myself and the shop) were curious to see if that fixed the Keyless Go feature but it did not.

Rudeney

If KG and the S/S button are all working, then you should get a "key not detected" message on the MFD if it is having a problem recognizing the key. Since you don't get that, it could be a bad S/S button, or it could be a problem with KG itself. Here are some tests:

Make sure the key is away from the vehicle (10ft) and try pressing the lock buttons on each of the outer door handles. You should get a "key not detected" message int he MFD. You can also lock the car, keep the key away, and try opening the doors and trunk - you should get the "key not detected" message. Note that you may have to try the handles and buttons several times before the message appears. If none of this works, then KG is not operating. Did you check the fuse? If this works, then do the same with the key in your hand. If you get a "not detected" message, then you may have a bad antenna. But not all the antenna should not be bad - some should work (i.e. passenger side or trunk).

sdwtchlvr

Yes, when the key is away from the car I get a key not detected when trying to lock and unlocking using the handle. Happens everytime I push the button trying to lock and unlock using the inside of the handle.

Rudeney

Do you get the same messages when the key is in proximity? And do you get the same messages at all exterior points int he car - driver door, passenger door, and trunk? If you are getting no messages when pressing the S/S button, then it is possible that it's a bad button, but it could also be the wiring - it goes from the button, through the shift module, and directly to the EIS (ignition switch). There was a forum member in recent months that had a problem with his button and I think it ended up being a bad EIS - he tested it by grounding out the input at the EIS and it was still not recognized.

Before I'd go digging into wiring, I'd first check the fuse, then test each antenna. If you get nothing from any antenna, then try another key (assuming you have more than one, and you should). also change the battery in the key.

Here are some diagrams that might help you understand how the KG system works:

http://benzbits.com/r230/KeylessGoZones.pdf
http://benzbits.com/r230/KeylessGoComponents.pdf

sdwtchlvr

Just got home to test these things. So I get the same messages with the key on me, "Key not detected" and the same message when pushing the S/S button. What do you think? Seems like the handles and S/S are working but just not recognizing the key? Could all the antennas be bad? I will check the fuse tomorrow...but if the fuse is bad, what should I test next?

Rudeney

I really doubt all the antennas would have failed. It could happen, but it's very unlikely. Do you just have one key? If not, do all keys have the same problem? It's possible the key has failed.

sdwtchlvr

I have 2 keys. Both keys get the same results. The car is in the garage right now. I put my hand on the black button or on the inside of the handle without pulling and the dome lights come on and the cluster lights up, key not detected. Something is up. Should I try replacing both batteries in my keys?

Rudeney

That is normal behavior when operating the handle sensor or outer door lock button without the key detected. Your problem seems to be that the system is not detecting the keys. Like I said, I can't believe all the antennas have simultaneously failed or that both keys have simultaneously failed. That is why I suggest checking the fuse.

If the fuse is good, then check for RF interference - drive to a wide open space somewhere, away from other cars, building, electrical wires, etc. and try it. If all that fails, you're going to need to get it hooked up to SDS to get a proper diagnosis.

sdwtchlvr

Will check the fuse today.

In doing a little reading, others that have had this issue with other models have either been told to put their key fob in a case and/or replace the antenna in the trunk area. Just the trunk antenna was mentioned for some reason. Is that the main antenna?

sdwtchlvr

When I'm in the car with the key fob on me and pressing the S/S button, I can hear a very faint rapid clicking, sounds like it may be coming from behind me. It happens every time I press the S/S button...and then the key not detected message pops up on the cluster a second later

May be worth noting, the trunk in my car had water damage from a faulty trunk seal. The car spent most of it's life in the Monterey Bay area and was driven very little over the last 3-4 years. Due to the water damage, the pneumatic system was replaced a few months ago by the previous owners. I'm not sure where the antenna is in the trunk but could it be that this was damaged by the water as well?

sdwtchlvr

I checked the fuses and the KG fuse (58) should be a 7.5amp fuse but a 10amp fuse is in it's place. All of the other fuses are the correct amps in this fuse box, just fuse 58 looks to be incorrect. I'm assuming this could be the issue? See the pic of my fuse box below...58 is the second fuse from the right.

Rudeney

Correct - 2nd fuse from the right is #58 and it should be a 7.5 amp, but a 10 amp would work, but it's best to use the proper rating for safety. I suspect if you had water in the trunk, then that is your problem. The KG control unit may have been damaged. Below is a photo showing its location on the left side of the trunk. The trunk antenna alone being bad shouldn't cause the rest of the system to fail unless it's shorted out and thus shorting out the control unit in some way. I have a photo of it below, too. I guess you could try unplugging the trunk antenna and see if that makes things work again and that would rule it out as being the culprit, but since you have the PSE pump replaced due to water damage, and the KG controller is right there, too, I'll be it's that. Sounds like time for SDS!

sdwtchlvr

I bet you're right on the keyless go control module. Where might I find a part number for that? I might just try picking one up on ebay. I'll see about having it checked out on the SDS. Is that something that a tech would need to be specifically looking for/testing or would it just pop up when hooked up to SDS?

Rudeney

You could try replacing the KG control unit, but you're just "throwing parts at it". It would probably be better to get a proper diagnosis. With SDS, the tech will need to specifically go into the test for KG.

Also, here is a document regarding programming KG keys:

http://benzbits.com/r230/KeylessGoProgramming.pdf

sdwtchlvr

Today I had some services done to my SL, essentially all of the fluids changed. I had the shop test the keyless Go module and the antennas to trouble shoot the keyless go issue, they said everything checked out fine. The took apart the gear shift knob to inspect the button. They did it as a courtesy as I really don't want to pay a ton of diagnostic fees to right not to fix this.

Do you think perhaps the batteries in my keyfob might be low? The car locks/unlocks fine using the buttons on the key fob. But when I try and open the top with the key, it has to be 1/2" from the handle and then the roof stops after a couple of seconds and doesn't finish opening. I'm going to replace the batteries tomorrow.

The shop also mentioned that my key might not be a Keyless Go key. I would find it odd if the PO swapped keys at some point and didn't replace with a Keyless Go key, and both keys?

Just wanted to give an update!

Also, something random happened last week, but maybe it's normal. I approached my locked car last week and popped the trunk with the key fob to put some wine back there. Then I got a call and the car system woke up and my phone was ringing through the blue tooth. Then when I canceled my car, the radio stayed on and was playing...is that normal? I hadn't gotten into the car yet, was just back by the trunk.

One more thing, is there anyway to have the audio system turned off but still have the nav map up? Seems like when I turn the audio/radio/sat/etc off, the screen goes dark. Then when I press map, the radio pops back on. Have to mute it to cut sound out. Is that normal?

sdwtchlvr

Changed the batteries in the fobs, still the same. Can anyone confirm that their keyless go key has 2 batteries or 1 battery? Each of my keys has 2 batteries.

Rudeney

I do not believe it is possible to get a "non-KeylessGo" key for a car that has KeylessGo. Keys have to be ordered through MBZ and they know by VIN whether the car has KeylessGo or not. If you have the key below, it will have two batteries: