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Diesel isn't a dirty word
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Getting spare keys working on the MK4 platform can be a bit of a nightmare at first glance so here are a few pointers:

Key overview:

There are four types of key on the MK4 platform all have an immobiliser transponder fitted to facilitate starting the vehicle.

1. Standard non-remote key

noneremote.jpg


2. Emergency key (plastic):

emergencykey.jpg


3. Two button remote early type:

round1.jpg


4. Two button remote late type:

sqr1.jpg


The two button types can be separated in two by grasping the key firmly in both hands and pulling the two halves apart, the top half with the buttons contains the remote control for locking and unlocking the car and the bottom half has the key blade and immobiliser chip inside.

Top

roundtop.jpg
squaretop.jpg


step1.jpg
step2.jpg
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step4.jpg
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Bottom

btm1.jpg


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DSCF0295.jpg
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The immobiliser chip is highlighted in red in the last picture, these are made of glass and are very fragile - they are glued into the original VW keys and are next to impossible to remove without breaking and once cracked they don't work.

Spare Keys \ Remotes

1. Remotes (top half of key)

If you want a new \ replacement remote fob then you need to make sure that the part number and frequency of the remote matches your current key fob. The replacement key fob can be a used item.

To check your current key frequency you need to separate the key in half then turn the top half over, on the back is the part number and frequency info

info.jpg


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There are two frequencies make sure you get the correct one!

Update courtesy of Ray :)

Check the part number not the frequency only.

HLO IJ0 959 753 A - All vw's from 1997 - 2000. HLO 1J0 959 753 N is usable and superceeds the older oval key used previously!

HLO 1J0 959 753 AG - vw golf's only 2000-2004. HLO 1J0 959 753 CT now superceeds the older part number hlo 1jo 959 753 AG.

HLO 1J0 959 753 AH - vw passat's/bora's generally. HLO IJ0 959 753 DA superceeds the older AH.
2. Keys (bottom half of remote key or standard non-remote type key)

As the key bottom half contains the immobiliser chip there are a few things to look out for when buying a new \ replacement key, as keys that have been coded to an immobiliser 3 vehicle can't be recoded to a new vehicle as the chip is write once.

Ideally buy a completely new key that has not been coded to another car before.

If your car is immo2 based:

You can buy a second hand key but you will need a new key blade to be cut, however the key can't have come from an immo3 vehicle as it can't be recoded

If you car is immo3 based:

The immobiliser can't be second hand (used), you will need a key bottom with a virgin transponder fitted to enable it to be coded to your car. So that means either

  1. A brand new key bottom half or
  2. A Second hand one with a new blade and then you will need to get a new transponder sepperately, Hickleys sell the transponder (AKTP2).

Beware on eBay when looking at keys, the add may say new key blade fitted, this however does not mean that the transponder chip is new and uncoded so you might end up with a key that unlocks the car but can't be coded to start it afterwards - If in doubt explicitly ask the seller if the key has been coded to a vehicle or not and does it contain a virgin transponder.

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If you need a new key blade for a key there is a seller on Ebay that supplies new blanks cut from a digital photo :Y:

Once you have your new key it will need coding to your car, you will need the SKC (secret key code) to match the immobiliser chip to the car but you don't need the SKC to match the remote part for locking and unlocking the vehicle, some older cars had the SKC provided on the key tags that came with a new car. If yours didn't then it can be retrieved with some third party tools such as Vagtacho.

VCDS (VagCom) can't retrieve the SKC code

Hope that helps

Neil
 

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uk-mkivs
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First class Neil, all the info in one place & clearly laid out![Y]

Had to do this recently for my mate who only had 1 key for his passat.
 

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Diesel isn't a dirty word
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Discussion Starter · #4 ·
I thought you could code a key using VCDS and don't need the SKC code?
If you are coding the remote then you don't need the SKC but if you are doing the immobiliser chip then you need to log into the cluster first then adaption chanel 21 and code the keys.

Neil
 

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I thought you could code a key using VCDS and don't need the SKC code?
If you are coding the remote then you don't need the SKC but if you are doing the immobiliser chip then you need to log into the cluster first then adaption chanel 21 and code the keys.

Neil
So in summary, if I get a new key and swap the blade section across I can just use VCDS to program the remote and thats it, but if I want to use the new key section, apart from getting the key cut, i'll need the SKC and VagTacho?
 

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Diesel isn't a dirty word
Joined
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11,031 Posts
Discussion Starter · #7 ·
I thought you could code a key using VCDS and don't need the SKC code?
If you are coding the remote then you don't need the SKC but if you are doing the immobiliser chip then you need to log into the cluster first then adaption chanel 21 and code the keys.

Neil
So in summary, if I get a new key and swap the blade section across I can just use VCDS to program the remote and thats it, but if I want to use the new key section, apart from getting the key cut, i'll need the SKC and VagTacho?
Yes, if you want to just use the remote then you just need to pair it to the car, either by Vagcam (VCDS) or the key in the door method. But if you want to use the lower half with the immobiliser you will need the key cut and the SKC code to pair it to the car.

Neil
 

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V6 4Motion
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Thank you for this - you just saved me £20 or more - I have been looking at getting a second-hand key for my immo3 and thought I'd covered everything. One bit that escaped my attention was the need for a fresh transponder !
 

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Thank you for this - you just saved me £20 or more - I have been looking at getting a second-hand key for my immo3 and thought I'd covered everything. One bit that escaped my attention was the need for a fresh transponder !
The transponders are pretty easy to get from Hickleys

the MKIV (non CAN based) uses the AKTP2 transponder (£7.47 inc VAT & P+P) and

the MKV (CAN based) uses the TP23 transponder (£21.27 inc VAT & P&P)

BTW great write up Neil [Y]
 

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uk-mkivs
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Who are the members that can get hold of new keys with virgin transponders?

I would like an upgrade to the newer button square version if anyone can help please.

Current key part no: HLO 1J0 959 753A 433mhz.
 

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uk-mkivs
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Can someone confirm if this key is suitable?

After doing an OEM electric window install I only have one key now and have got another one off the bay.

I have a key part no. HLO 1J0 959 753 AH 434MHz (Square 2 button).

Key from ebay I have been told by the seller is a replacement for other model nos. HLO 1J0 959 753 CT 434MHz (Square 2 button).

I know about the immo chip & all that, just need to know if the remote section will work as the seller says.
 

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Noticed this evening that my only key is breaking - the pin that holds the blade on fell out because the metal is cracked. Tried to open the key to get the codes off it, and it's absolutely stuck solid (I think I can see traces of glue [:(])

Is there another way to get the codes, or am I going to have to go and pay VW's extortionate prices for a new one?
 

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Similar problem here ABM , mine is that i dont have a remote key fob to start with , only the spares so where do i start trying to figure out which part number? On other cars ive had the alarm ecu etc have helped me figure it out but i dont even know where it is on this car!

Any tips?
 
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