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Picture of Repair Hyundai or Kia Flip Car Key
key wear n tear.jpg

Photos: 1) New key from aliexpress, 2) An old key showing some wear n tear.

This is a very rough guide to replacing the faulty case (fob, shell) of your 'flip' car key. This guide does not include replacement of the internal transponder and circuit board. If the former is you, then you're in luck as the process is relatively straightforward - you can do it!

I couldn't find anywhere that sells just the button pad, to just replace that. If you do not want to replace the entire key case, and only want to replace the button pad, try the link at the bottom of this page. You could order the key case, and cut out the button pad from the new key. I preferred to replace the whole case.

I was quoted between NZD $350 - $450 to purchase a replacement key, by Hyundai NZ and key cutting shops. They would not repair it.

I did this repair for $7.00 total, excluding my time (but the satisfaction was worth it). I already had several of the standard/basic tools that I needed. I'm not sure on the rules of 'Instructables', but if you want me to do this for you, get in touch.

Warning: this guide is only valid if you still have the (now defunct) key(s), as you'll need the innards/electronics to swap into the new case. If you've lost the keys, this guide is not for you (you may have no option but to go to the car manufacturer/agent). Also, if you've only got one key, and you're REALLY not confident, perhaps paying $350 is a better risk than stuffing up the only key you've got and paying a lot more for a whole new set.

My car is a 2012 Hyundai i40. The key case I purchased, from aliexpress (see search criteria below), was a perfect match.

You may not know what the inside of your key will look like to find the exact match. If you're reading this, you've probably run out of other options, so I suggest you open the case of your busted key, assuming it's a common car brand. If it all goes pear shaped, you'll at least be able to take the electronics to the $350 option and swallow your pride (perhaps check with them first). Or just go online and find the replacement case you think will be the exact match, spend a few dollars and order it, and if it looks the same on the outside, there's a good chance it'll be ok on the inside.

The Car Key Man provided the inspiration that I could do it. I recommend his video, probably before continuing with this.

I purchased the key case from aliexpress: search "KEYYOU 4 Buttons Flip Folding Remote Key Shell Fob Case For HYUNDAI Mistra Santa Fe Sonata Tucson Accent I30 I40 I45".

Step 1: Open the Old Case

Picture of Open the Old Case

A) take off the rear battery cover. This should just pop off with some thumb pressure.

B) remove the battery.

C) There are two possible ways to open your old case.

1) the case sides have been clicked together and will simply pop open with some pressure applied to the seam around the middle, as shown by twisting with a chisel.

2) the case is a single solid piece. The 'seam' is just for show and wont 'crack' open.

This is the time consuming part.

Using a soldering iron*, melt the plastic around the fake seam. Work down through the plastic slowly, so as not to damage the circuit board. As you get around the edge of the case and it starts to come apart, be careful to catch anything that falls/springs out.

*If you don't have a soldering iron handy ($10 for a cheap one), you could similarly use a hack saw.

The last photo shows the end result. The boxes highlight the (top) transponder cover, (lower) a circuit/button cover from the circuit board that fell off when opening. Easily re-affixed.

АхмедА2 months ago
JanK2406 months ago
I almost never comment on the world wide web. But I felt inclined to comment here because your instructions and particularly spring component saved me from going to the dealership which surely would have taken me to the cleaners. Thank you!
mattm393 (author)  JanK2406 months ago
Know what you mean... Glad it helped!
supertin1 year ago
Nice work. I had most of the process worked out on my own, but that dang spring had me stumped. Your pictures were worth 1000 words for that part.

Clever hack.

Thanks. Just glad it worked, and hope it saves someone else some $.