BMWtoAMG

Hello folks,

My wife's car (2021 GLC 300) has a bad habit of 'forgetting' the garage door opener's code. Will program fine, then needs reprogramming within a week or so. Opener is a Lift Master from around 2017. Anyone else experienced this?

Certainly possible that's it's unique to this brand of opener, as we had no such trouble when pairing with a newer Chamberlain. Worse comes to worse I'll have MB look at it at next time it goes in for prepaid.

TY all in advance!

mikapen

It sounds like you may not have completed the second step in setting up your garage door opener.
That's the step that synchronizes the rolling code feature.

Let's try starting over by doing the two-step.

BMWtoAMG

Appreciate the reply! Maybe I'm missing something...but here's how I program, which is I believe what you are referencing

1. Clear mirror memory
2. Put mirror in program mode by pressing button I want to use until LED slowly flashes
3. Press/hold remote near mirror until mirror LED flashes green
2. To sync rolling code, hit learn button on garage opener then, while that LED is flashing, repeatedly press programmed button on mirror until a) garage opener light flashes twice and b) garage door opens/closes

My current C 43 was programmed to the same garage opener this way 2 months ago and it has never lost programming...why it seems something is up with the GLC.

superswiss

You may have to vary the procedure slightly. At the link below (scroll to the bottom of the page) you can get the specific instructions for your vehicle and specific garage door opener. The buttons have to be pressed for a specific length of time. Don't know if MB recently updated the Homelink transmitter, but they are largely shared between models and model years. Homelink hasn't changed much in recent years, except for the new Security+ 2.0 standard, which openers manufactured after 2011 use. These have the yellow learn button and yellow antenna and require a compatibility bridge for vehicles manufactured before then, but both your C43 and GLC have Security+ 2.0 capable transmitters.

https://www.homelink.com/program

BMWtoAMG

Great info. Thank you for this--after a read it looks like I'm doing things correctly.

superswiss

Also, one thing to be aware off, garage door openers can only hold a fixed number of remotes and they start kicking out remotes or become unable to program if they reach the limit. You may wanna reset your garage door opener and clear all the remotes from it. If I remember correctly that's done by pressing and holding the learn button for several seconds. Unfortunately, you'll have to reprogram all your remotes again, but you'll start with a clean slate. I usually do this every time I sell the current car to clear the transmitter from the system.

BMWtoAMG

Have cleared the opener, remote, pad, both Merc Homelinks, and reprogrammed everything. Fingers crossed, but gut feeling is this will be yet another issue with this particular vehicle that has the wife wanting to go back to Lexus or BMW. The vehicle is not the same since the warranty cylinder head replacement in March. I expect better from Mercedes, especially one built in Germany. The first 40K only required routine maintenance, but this last 5K has me wondering if we have the bad luck of buying a less than stellar example of the facelift X253 that was assembled during Covid. Glad to have the extended warranty in this case.

Thank you all, and if it's good after two weeks I'll call it sorted. Either way I'll update!

DanD.

Just a wild guess: how long do you keep pushing the button? Does it affect a stored code if you hold it for too long?

mikapen

And do you need to wear a certain color clothing?

streborx

Superswiss is correct in post #6. Strange things can happen when the door opener reaches its pairing limit. Hopefully clearing and reprogramming has done the fix for you.

BMWtoAMG

Back with an update, folks. Was going to in fact post today that clearing everything fixed it--but this morning it stopped working. At least I got a full 2 weeks this time before having to reprogram.

Will have MB fix this next time it goes in for prepaid maint. Will update when that occurs, have a few thousand miles to go.

672club

sort of related. older (than your) liftmaster with any remote intermittently successful. service replaced led light bulbs with non led and now all good

superswiss

Yes, LED light bulbs unless specifically designed for garage door openers can interfere with Homelink. Liftmaster sells compatible LED bulbs. https://a.co/d/6SwFcqp

BMWtoAMG

I learned something new today. Interesting, and I do have an LED bulb in the opener that was just now swapped out with halogen as a test. Trying to keep an open mind given the C43 has always worked perfectly, and still does. Worst case I just swap the LED back in. TY you both for the info. Fingers crossed.