Cheaper solution: Repair a faulty BMW key

BMW provides replacement key chains for obscene prices, as I understand it, up to Rs 60k.

BHPian dinu2506 recently shared this with other enthusiasts.

I’m not sure about the latest BMW cars but the 2012 BMW X1 I have and the 320ds etc. from this period in India would most likely have fully sealed key chains. These are referred to as “uncomfortable access” key fobs. In world markets, there are also cars equipped with “Comfort Access” key fobs with a replaceable CR2032 battery, which is standard in most other cars. I still don’t know why we were given the ‘No Comfort Access’ key fobs. These are fully sealed units with a rechargeable battery called VL2020. These are meant to last the life of the car, which will likely be the case if used the way it is meant to be used and the dealership specifically notifies buyers.

But I don’t remember my dealership telling me about it when I bought the car and it was only recently that I learned (after one of them broke down) that the key fob comes with a non-replaceable rechargeable battery. The correct way to use key chains is – either the two key chains are used in parallel by two people or if only one is used at a time, be sure to change the key chains at least once every 3-4 months to be on the safe side so that they are charged during use. FYI, the key fobs charge wirelessly when inserted into the slot when using the car. Unfortunately, it was too late by the time I read and understood about this. One of the remotes had been unused for over 18 months and when I tried to use it it was dead and the doors would not close or unlock. The other remote worked perfectly. Now started the surveys and was shocked at the options.

BMW provides replacement key chains for obscene prices, as I understand it, up to Rs 60k. I checked with my FNG and they couldn’t help me either and said we need to get the replacement from BMW but said he could convince the dealership of a goodwill warranty and l ‘get it at a cost of 50%, which in itself was too much for me. The point is that the key fob still works when inserted into the slot and the car starts and runs (later I found out that in order to start and run the car the battery is not at all necessary). Locking and unlocking should be done manually using the physical sliding key. It was good for me and made me decide that I don’t spend that kind of money to buy a new one. I tried recharging the key fob by placing it on wireless phone chargers overnight and also connected the car battery to a charger and left the car on overnight. But nothing worked and the key fob could not open and close the doors. So, I concluded, either the battery was totally dead to the point that it cannot be recharged or there is a problem with the PCB. The gut feeling was that the battery died because I barely used this keychain.

During this time I also started to google and came across many videos where people opened the key fob, unsoldered the VL2020 battery and replaced it with a new one, resoldered the terminals and sealed the case. . I wasn’t sure if I should try it as there were also a lot of reports where it didn’t work even after replacing the battery. First, I checked the availability of the VL2020 battery – it is the same size as a CR2032 battery but has riveted pins at a 90 degree orientation for the positive and negative terminals. There are also 180 degree oriented pins, but the X1 keychain needs one with 90 degree orientation. Not available for free and none of the popular sites had them but came across a STOPSHOPSWIPE seller that was selling for around Rs 1300.

Before placing the order, I mentally prepared myself to open the keychain. The reason was this. First, I had a working key fob, second, I knew the battery was only needed for opening and closing, so in the worst case if it doesn’t work I can still use the key physical. Opening the keychain was much more difficult than I expected. It’s a very strong gasket all around so you need to use a really good solid blade and be very careful not to insert it too much inside and damage the PCB without knowing it. Never try to open with a screwdriver or anything, it will damage the case for good and eventually render it unusable. Once done (it took a good half day and a lot of patience to do it in two halves), and unsolder the VL2020 from the PCB. I checked the voltage and was only showing 1.69V (compared to nominal 3V) which was the reason it couldn’t recharge. Before placing an order for a new battery I still wanted to check if it was a battery issue and thought of a jugaad. I had a CR2032 lying around, soldered short wires to the positive and negative sides and connected those wires to the points I unsoldered on the PCB. I took the PCB with the jugaad CR2032 and pressed the buttons on the PCB. The X1 happily unlocked and locked. The third button to open the tailgate also worked. He was now certain that it was just a battery issue.

Immediately placed an order for VL2020 battery with 90 degree pins. It was frustrating. They took a full 6 weeks to deliver this item to me, despite repeated follow-ups. Eventually it happened and I immediately started soldering the new battery. I took the PCB to the car and it worked. I brought it back, placed it inside the remote control case, and used Fevibond to seal it. Like I said, there’s no way to avoid damage when opening, so it’s pretty much impossible to get a clean edge when reassembling, but not too bad either. I called on the services of my daughter, who has firm hands and knows how to paint well, to touch up the edges with black enamel paint. All in all, a worthwhile effort, and really happy and content to bring the keychain back to life.

I guess a lot of BMW owners might be dealing with this or probably haven’t even realized that one of their key chains is dead. Hope this could help you with a solution rather than spending a lot of money on a new one.

Key points:

  • If you have both remotes working, make sure you keep using both and don’t leave anyone unused for more than 6 months – this is something the dealer should tell buyers.
  • Be very careful using the blade to open. Invest in a good quality blade and make sure you go just deep enough to cut the joint and no more
  • Have a lot of patience while doing the above
  • It is a small PCB, so be careful when desoldering and re-soldering so as not to touch or damage any circuits nearby
  • Be prepared to accept a certain amount of damage to the edges of the case where the knife is used, this is inevitable
  • Never try to open with objects like a screwdriver as this will definitely break the case – you have to cut all around with the blade.

The following images should give you an idea and I hope they help you!

Here is what govigov BHPian had to say about it:

Very useful DIY and it should be informative for many BMW owners. Even with 2 people driving the car, it is customary for Indian families to keep a key safe while the primary key changes hands. In situations like this, it is inevitable that this will happen

Also, another lesson is, be sure to check both keys when buying used BMWs, and don’t think it’s an easy matter to change batteries.

Thank you so much.

Here is what BHPian OEMplus55 had to say about it:

Fantastic thought, thanks for sharing with us. I never knew this was a potential problem with the key chains. The enticing replacement prices seem squarely intended to squeeze customers dry just because of brand value. Love that you refused to take a ride just because their company policy went for ridiculous prices.

Do you have any idea what the commission looks like for dealers on these? Even with the 50% discount offered, their margins could be significant. Maybe that’s one reason dealers don’t really talk about it. At least in my experience with high end dealers in India or overseas, I have never heard this topic mentioned.

Will definitely let your friends and family know that they need to switch usage between master and spare keys!

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