Replacing the Battery in your Aston Martin Crystal Key Fob

If you have a later model Gaydon era Aston Martin DB9, Vantage, DBS, Rapide, Virage or Vanquish you likely have a pair of Crystal Key fobs, and one less fancy plastic Valet key.   Aston’s marketing team called the sapphire crystal key fobs Emotional Control Units (ECUs) – uhh, sure.  Like any modern automotive key fob they have a battery inside them that powers the transmitter for the buttons that lock and unlock the car.   Aston Martin’s service schedule recommends that the batteries be replaced each year during the annual dealer service.   While that’s the most conservative approach, you can save yourself some money and do it every 2-3 years, or even just wait until it stops working to tackle it yourself then.   It’s a very easy procedure you can tackle in just a few minutes on the kitchen table at home.  Let me show you how.

Frequent readers of this blog are probably thinking “Wait, what?   Doesn’t he have a 2005 DB9 with the ugly Volvo key and fob”.   You’d be right.   Recently I saw a great post about this by Andrew Hwang on the Facebook Group – Aston Martin DIY (All Models).  I highly recommend you join this group as it’s a great resource.     I contacted Andrew and asked if I could re-publish the information here and he was nice enough to supply the photos and basics of the write up (Thank you Andrew!).   I’ve compiled it along with a few of the additional tips that came in as comments to make this guide.   I’ll publish an article on how to change the batteries of my Volvo fob separately soon.

It surprised me that Aston Martin does in fact recommend that the key fob batteries be replaced at every annual service.  I replaced my Volvo fob batteries 9 years ago and they are still working.  This standard makes no allowance for use or condition, just an automatic replace.   Probably too conservative for me, and I bet they charge $35 or something to change each one.  Here is an excerpt of their vehicle maintenance check sheet.

Parts

You need a new CR2032 battery.  This is a very common coin cell battery type and you can probably get nearly anywhere.   If you are going to do all three keys routinely, you might buy a 6-pack of Energizer brand batteries from Amazon for about $7 USD.

Tools

You need a couple of screwdrivers.

The first is a tiny flat head screwdriver you can best source from an Eyeglass screwdriver kit.   Typical shop screwdrivers are far too large.  Make sure you have a good one as you need a nice tight fit in the screw head so you don’t damage the slot.  You can probably source a kit locally, but if needed you can purchase a nice kit for about $8 USD on Amazon.

The second screwdriver is just a typical small flat head you’d have in the shop.

Procedure

This should only take you about 15 minutes sitting at the kitchen table where the light is good.

The process is different for the Crystal keys and the plastic Valet fob.  Let’s start with the Crystal Key.

Crystal Key Battery Replacement

  • Be careful with your Crystal key.   If you break the key Aston wants a whopping $1,650 for a replacement key and it requires programming at a dealership.   Now on with the show.
  • Using the eyeglass screwdriver remove the two screws out at the bottom of the FOB.
  • Slide the metal silver trim down to separate it from the plastic body.
  • Slide the main unit out the side.  Be prepared for the buttons to fall out of the the shell if they are facing up like in the picture.  To keep the buttons in place you could face the unit down so they stay in place.
  • Using the eyeglass screwdriver unscrew the six (6) small screws of the battery cover.   Select a screwdriver with a tip that fits the slot as tight as possible.   Keep the screwdriver tip in tight as you loosen it off so that you don’t strip the slot.
  • Remove battery and replace
  • Install is just the reverse, but a couple of tips:
    • Perhaps write the month and year on the battery face with a Sharpie marker so you have a future reference of how old the battery was.
    • Go careful with the little screws on the battery cover as the heads break pretty easily.
    • Now is the time to bust out a microfiber towel and clean those buttons on the fob.  You can get into the nooks and crannies with them out.
    • Do not over tighten the case screws when you put the body back together as you could strip out the threads in the plastic.

Plastic Valet Key Battery Replacement

  • Take eyeglass flat head screwdriver and carefully pop off the top as seen in this photo:
  • Use your larger shop sized flat head screwdriver to carefully pryse the housing apart until it spilts the key into two
  • Remove and replace battery
  • Carefully align and snap the two halves back together and the clip the top piece back on.

Now relish in the self satisfaction of a job well done and a few dollars saved.


Videos

Since I don’t own a glass key car, I haven’t shot any videos myself.  But, I found this video from Josh of DetailCorpsMedia did a mini tune-up of his Vantage valet key.

 

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