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SL-Class (R230) 2003 -- 2012: Discussion on the SL500, SL550, SL600

Help! Key Fob not detected

 
Old 04-12-2019, 08:56 AM
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Help! Key Fob not detected

I noticed it yesterday morning, I went to my car and noticed that it was unlocked 🤔, I know for sure that I locked it the night before, so I get in the car and push button is not working, and a display saying, key not detected. So I manually inserted the key and drove to work, I know that the batteries were just replaced 2 months ago, after work, I got out and discovered that my car is unlocked? I then try the push button and it worked. This morning, I took my second key fob and it still saying key not detected? Everything else is working fine with the key fob but not push button start.

Thanks!
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Old 04-13-2019, 07:10 PM
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Is Rodney on vacation, I wonder?

I read the above post and find it a bit confusing. There seems to be two issues: (1) the vehicle is unlocking by itself, and (2) KeylessGo is inconsistent.

At any rate, I know both Rodney and I have responded to questions like these in the past. If you search on "Keyless" you may locate some of those useful posts.
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Old 04-13-2019, 08:31 PM
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Originally Posted by bobterry99 View Post
Is Rodney on vacation, I wonder?

I read the above post and find it a bit confusing. There seems to be two issues: (1) the vehicle is unlocking by itself, and (2) KeylessGo is inconsistent.

At any rate, I know both Rodney and I have responded to questions like these in the past. If you search on "Keyless" you may locate some of those useful posts.
Thanks for your reply, the unlocking has stopped, it hasnít happen again. Just the push button that not working. I finally scanned the car today with star, Iíll post it soon.
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Old 04-13-2019, 08:34 PM
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I ran star Diagnosis today and found this


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Old 04-13-2019, 09:47 PM
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Sounds like a problem with the door lock. Normally, it's pneumatically operated, but with KeylessGo, it also has an electrically operated servo (since the pneumatic function would be too slow to unlock it when grabbing the handle and pulling it to open the door. My guess is that this is what keep unlocking your door (or not letting it lock in the first place). The "key not detected" message is likely unrelated. If that's caused by batteries in the fob dying, and they keep dying, it could be that you are storing keys too close to the car. They need to be kept at least 12 feet away to prevent constant communication with the car.

BTW, I only wish I were on vacation. We have decided to sell our house and move. We have lived here for the last 22 years and I've been working feverishly to get some things fixed and touched up before putting it on the marker, which we did today and had our first showing. I still have some little things to do, but the big stuff is done.

Last edited by Rudeney; 04-13-2019 at 09:51 PM.
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Old 04-21-2019, 07:39 AM
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Just replaced the batteries in my key fob, still getting the key not detected when I press on the push button start. Will this be a fuse issue?
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Old 04-21-2019, 11:30 AM
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Do any other KeylessGo functions work? With the car locked, does it unlock when you grab the door handles (try both)? Do either of the door handle lock buttons work? With the car locked, can you open the trunk with the key nearby? If none of these work, then it sounds like the KeylessGo controller is the problem. Check fuse 58 on the rear panel (under the stowage compartment, behind the passenger seat). If some work and some don't, then you may have a bad antenna - you can use SDS to test them and diagnose that. Also, check the KeylessGo controller for water intrusion - it sits below the NAV disc drive on the left side of the trunk.
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Old 04-21-2019, 12:59 PM
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Originally Posted by Rudeney View Post
Do any other KeylessGo functions work? With the car locked, does it unlock when you grab the door handles (try both)? Do either of the door handle lock buttons work? With the car locked, can you open the trunk with the key nearby? If none of these work, then it sounds like the KeylessGo controller is the problem. Check fuse 58 on the rear panel (under the stowage compartment, behind the passenger seat). If some work and some don't, then you may have a bad antenna - you can use SDS to test them and diagnose that. Also, check the KeylessGo controller for water intrusion - it sits below the NAV disc drive on the left side of the trunk.
No, the trunk will not open even though I have the keys in my pocket. I used to just placed my hand on the handle and the door will open, now it doesnít. The button on the door has never worked, I got it like that.
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Old 04-21-2019, 01:35 PM
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Originally Posted by Rudeney View Post
Check fuse 58 on the rear panel (under the stowage compartment, behind the passenger seat).
Is fuse 58 a 7.5 amp? I only found two 7.5 amp fuses and I replaced both, no luck.
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Old 04-23-2019, 07:50 PM
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Yes, 7.5 amp. Here's a comprehensive set of fuse charts I ripped from WIS:

http://benzbits.com/r230/Fuses/

At this point, you need to hook it up to SDS and scan the KeylessGo controller for error codes, and also you can test the various KG antennas.
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Old 04-23-2019, 08:32 PM
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Originally Posted by Rudeney View Post
Yes, 7.5 amp. Here's a comprehensive set of fuse charts I ripped from WIS:

http://benzbits.com/r230/Fuses/

At this point, you need to hook it up to SDS and scan the KeylessGo controller for error codes, and also you can test the various KG antennas.
I hooked it up with SDS when this issue started initially, Iíll hook it up again... Attached, is what I found when I did the scan.
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Old 05-04-2019, 08:20 PM
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Did another scan today

It looks like all the antennas are fine.









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Old 05-04-2019, 09:54 PM
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This is the test you nee to use for the antenna - place the key in range and rerun to make sure the keys are seen:

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Old 05-04-2019, 11:47 PM
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Originally Posted by Rudeney View Post
This is the test you nee to use for the antenna - place the key in range and rerun to make sure the keys are seen:

I did... the keys were right on my lap when I ran this test.
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Old 05-06-2019, 11:37 PM
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You need to run the test with one key at a time, and in the four possible locations: outside each door, outside the trunk and in the cockpit. If it still fails, then it sounds like a defective KG control module.
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