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Discussion Starter #1 (Edited)
Hi guys,

I know this has been discused before, but none of the various threads reach to a final conclusion.

There have been several cases reported of keyless go not working after having the windows tinted. This is my case today. Tint used was 3M (non Metalic).

Some of the responses and theories from previous cases are:

(A) water used during tinting, damaged something (apparently) in the rear window.
(B) interference caused by tints.
(C) damage to some antenna or sensor during installation.

Some of the folks that have suffered this reported that they solved it by reprogramming their FOB, some others said it did not work for them.

So I was just wondering if there is a general conclusion about this. What is the update on those of you who suffered this problem? I know that some of you went to the dealer to have it serviced, what is the outcome? Is it a serious problem? How much did the repair cost?
I will apreciase your help.

Kind regards,
JS
 

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Its the rear window tint causing the issue. I had a similar problem when I tinted my CLA this summer. As soon as the tint guy finished I couldn't use the 'push to start' to start the car. I had to insert the key into the starter and turn it manually to start it.

Whats happening is that the rear window has important antennas (not just the rear defroster) and the tint is somehow shorting the antennas to the ground thus creating all sorts of issues with keyless go, keyfob, etc.

After a day once the tint dried up everything was working fine again. If after a day you still have problem you may need to have the rear window tint removed (carefully) to confirm the issue.

Good luck
 

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Discussion Starter #4
Thanks guys. Today (48 hours after tint was completed) I tried the FOB reset:

A) While being far away from the vehicle (Out of range of FOB reach), quickly press the lock button twice. This resets the FOB.
B) Go to the vehicle and open it using the unlock button, get in the vehicle, close the door and use the start/stop button as normal.

That worked for me pefectly. As 2016CLA_MTL mentioned, it might have been a combination of tint having dried up, and the reset of FOB. I am glad that it worked well.

Thanks!
JS
 

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The diversity antennae on the glass substrates are very sensitive to any "disturbance" to the electromagnetic field strengths ... even nonmetallic tint can have effects ... think back to your cellphone screens and elevator call buttons and how the disturbance from the tough of a finger causes effects (circuit activation in those cases).
Just glad after "drying out" those antennae still function and the receiver circuits have enough dynamic range to account for distorted incoming signals.
Good grief. ?
 

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Hello,

I had my windows tinted on my '16 CLA250 yesterday and I had the same problem - key would work to unlock, lock, etc. but push-to-start would not work and I got the "key not detected" message. Keys were less than 5 months old so I was pretty certain it had nothing to do with the battery. I tried it again today and voila, worked just fine. As some of the others mentioned previously, it must have something to do with the tint still being wet and interfering with the antennae, but once it dries it should be fine (assuming nothing was damaged in the process).

Good luck!

R
 

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Must be some capacitive effect since this whole scenario is essentially a parallel plate example and the fluid content affects enough to disrupt the antennae functions until it has either evaporated or the system normalizes.
But this makes one think if the tuning is so tight to avoid cross interference or accidental triggering... hmmm... typical Germans ??
 

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This happened to my 2018 CLA250 as well yesterday when I got my windows tinted in Miami. Had ceramic tint at 18% applied. My key wasn’t detected either. Waited roughly overnight and when I went to get in the car this morning everything was back to normal. I think it is the fluid that has to dry completely so it doesn’t interfere with whatever signal aligns with the key fob.
 

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I knew something was off when I got in the car and saw my key was in the ignition and I was like, ok why is that there as I only use the push to start feature. I had just replaced the battery so that was new as well. Did a lot of trolling through youtube to figure what was the issue, was about to go to a local Benz dealership until I came across this thread.

Slept on it overnight and boom, everything worked fine in the morning. Appreciate you guys and your input.
 
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