At the end of May 2018 I was looking for a project/fun car. My top requirements for this vehicle were that it should cost $3000 or less, it should have a manual transmission, that it should require no more than $1000 of repairs to be a reasonably trustworthy daily driver… and that’s pretty much it for hard requirements. I was hoping for a small 2-door car and I looked at some Minis, all of which were in extremely rough shape. Then I found a 2003 New Beetle (1.8L turbo, 5spd, GLS trim level, 87K miles one owner) on Craigslist for $3000 from a local dealer. It’s certainly not perfect, particularly the interior, but all its foibles seem to be things that are within my skill level and toolset, so I negotiated to $2800 and drove off with it. Here’s a quick walkaround as-is. Yes, I’m sure there are a bunch of things I haven’t discovered yet.
Today (June 10 2018) I flew back in from Indiana to be greeted by a pile of parts I’d ordered while I was away. I guess probably the simplest “repairs” I could make would be to replace the oil dipstick and the washer fluid reservoir cap, but I decided to go for what I thought was a simple indoor job I could do while having a cold iced tea and watching some Oz – viz. swapping the keyfob guts into a new shell.
At first glance, this looked like a very simple operation, and in fact I’ve done this to quite a few keyfobs in the past for different vehicles. There are, of course, YouTube videos of the activity. One minor complication for this particular fob is that it is the fancy style where pressing the silver button flips the key blade out of the fob, ready for insertion into the lock. The mechanism for this is, however, simple enough and it’s pretty obvious how to wind it up for the correct spring tension as you reassemble the housing. Depending on the condition of your original fob, you might not even have to bother with swapping out key blades – you might only need to replace the “remote control” half of the shell. There’s another route, also, which is to punch out the roll pin that holds the actual key “tongue” into the rotating bearing, and swap out just that tongue. This isn’t really recommended, but if you must do it, make sure you separate the key section from the electronics section before whaling on the roll pin, to avoid damaging the fob or PATS capsule (Passive Anti-Theft System; more on that later). The only reason I can think of that you REALLY might want to do this is if the rotating part of your original key is really badly beaten up. Mine has the usual dings from being carried in a pocket with other keys, but I’m certainly not troubled by this minor detail.
Taking both fobs apart was easy enough, though I’ll pause to note that removing the VW logo on the back to get at the screw that holds together the key portion is a destructive operation, and the new shells don’t usually come with logos (since they often cover several different marques), so you’ll have to order the right logo for your vehicle separately; I found a Chinese vendor selling a 10 pack for $3.99 shipped, vs $8 or more for a single original (?) part. More importantly, this key includes a separate PATS capsule, which is easy to miss if you aren’t expecting it. This is a small RFID tag in the key half of the fob; the reader is wrapped around the ignition switch in the car. If that capsule is missing or nonfunctional, the immobilizer will kick in and kill the engine. If you zoom into the picture at right and look closely at the component immediately under the small silver screw, you’ll see the capsule nestled down in a cavity – it’s surrounded by white deposits that suggest it was glued in with cyanoacrylate (super-glue). YouTube videos tell you to just yank it out with a screwdriver – this is a guaranteed recipe for breaking it. Because it was crusted with adhesive I couldn’t tell if it was completely encapsulated, or if it had an antenna wire wrapped around the exterior and protected only by a lacquer layer.
Thus, I had to proceed very carefully. The fob is made of a glass-filled polymer and is very durable – I wound up using a soldering iron to melt away material until I’d freed up the capsule, which you can see in my hand. As it turns out, it’s fully encapsulated, so it would survive minor scratches e.g. from an Exacto blade – but again, it’s made of glass, so extreme caution is warranted. If, like me, you have only one key, you’ll be in a ticklish position. (Memo to self: drop the probable $120 on a second key).
As a side note, I find this design odd. Here’s a picture of my 2007 DaimlerChrysler Jeep key, which has similar functionality. The large coil-wrapped ferrite rectangle you see just above the microcontroller is the PATS antenna. In the DaimlerChrysler design, however, all the authentication/crypto stuff – both RKE (Remote Keyless Entry) and PATS – is performed in a single microcontroller. This arrangement just makes much more sense to me when the electronics are physically integrated with the ignition key; you only have to program one uniquely serialized device, and you only have to “marry” one serial number/crypto key to the car’s computer. It feels like the VW/Audi solution was originally a standalone keyfob design (where the ignition key was hung separately on the same keychain) and rather than redesign the circuitry to integrate RKE and PATS when they moved the physical key into the keyfob body, they simply took the external RFID tag that they’d been molding into the separate ignition key and moved it into the fob body. Who knows, maybe they had lots of stock of tags and readers.
Anyway, that annoyance aside, the last remaining irritation is that the mounting pillars for the PCB were not quite in the right positions. The board was originally heatstaked into position, but because the spacing on the pillars in the new shell is wrong, it can only sit on one post. This means the board can swing out of alignment slightly, which makes the side-mounted panic button extra hard to push, but this is a button I’ll likely never use anyway, so that’s fine.
Miscellaneous other pictures are below for your pleasure.