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I took two actions in the last two days. I bought an Xtool and I contacted the vendor of the new ECU that I bought to see if they could supply the SKC. Here's another question: If I pull the ECU and I can't retrieve the SKC from the new one will I be able to put the old one back without a problem? I identified a local shop which specializes in this kind of work. It's within a mile of me so I'd feel OK driving the car over if that ends up being the way to go. I still want to try to do it myself.
You don't want the SKC from the new ECU, you want the SKC from the original ECU.
Once you have the SKC, you can code it to the new ECU (or a used ECU) with VCDS.
 

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Discussion Starter · #42 ·
You don't want the SKC from the new ECU, you want the SKC from the original ECU.
Once you have the SKC, you can code it to the new ECU (or a used ECU) with VCDS.
Interesting Tom. A little different from the info that I got above and VERY good news. Can you program the SKC into the new ECU without the car running? How about the keys? It would make sense to me that if you used the original SKC the keys would still work but I'm not sure.
 

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Discussion Starter · #43 ·
Interesting Tom. A little different from the info that I got above and VERY good news. Can you program the SKC into the new ECU without the car running? How about the keys? It would make sense to me that if you used the original SKC the keys would still work but I'm not sure.
Just perusing the Immobilizer 3 page in the VCDS manual under the swapping with a used SKC and it says this:
  • Make sure to have BOTH PIN's, from the ORIGINAL (OLD) and the REPLACEMENT (USED) ECU.
It looks like it can be done with a new ECU. I have a new one. I'm not totally confident in it's quality but it's worth a try.
The info came from this page:
 

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For a new ECU, you only need the SKC for the car.
But when using a used ECU, you will need the SKC for the car and the SKC for the used ECU.

The ignition must be on, but the engine not running.
A new ECU does not have a SKC set, so you can go straight to Adaptation and set the SKC to the PIN of the car.

The ignition must be on, but the engine not running.
When using a used ECU, you will need the SKC for the car and the SKC for the replacement ECU.
First you go to [01 - Engine], [Login - 11] and enter the PIN of the REPLACEMENT (USED) ECU, to unlock the module.
Then go to Adaptation and set the SKC to the PIN of the car.

In either case, the original car keys should work.
 

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Discussion Starter · #45 ·
For a new ECU, you only need the SKC for the car.
But when using a used ECU, you will need the SKC for the car and the SKC for the used ECU.

The ignition must be on, but the engine not running.
A new ECU does not have a SKC set, so you can go straight to Adaptation and set the SKC to the PIN of the car.

The ignition must be on, but the engine not running.
When using a used ECU, you will need the SKC for the car and the SKC for the replacement ECU.
First you go to [01 - Engine], [Login - 11] and enter the PIN of the REPLACEMENT (USED) ECU, to unlock the module.
Then go to Adaptation and set the SKC to the PIN of the car.

In either case, the original car keys should work.
Thanks for the clarification Tom. That lines up perfectly with the VCDS manual but it is nice to have verification from someone with experience. My Xtool arrived today and I was able to pull the PIN from the ECU pretty handily. It will be interesting to see if my $100 Chinese ECU works. I'll report back.
 

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Thanks for the clarification Tom. That lines up perfectly with the VCDS manual but it is nice to have verification from someone with experience. My Xtool arrived today and I was able to pull the PIN from the ECU pretty handily. It will be interesting to see if my $100 Chinese ECU works. I'll report back.
Could you go thru the process you used again and take photos of the XTool screens you use ?

The reason I ask is because the 4B0 ECU I have gave me the SKC code easy enough but I couldn't log in to the ECU afterward.

Retrieving the SKC from a 4B0 is different that the 3B0 (V6) or the 07D (W8) that I have.

This is what I get when hooking up the XTool :
102552
102553
102554

With the 3B0, I have to enter a 4digit code first to get the SKC, and I don't have that 16 - Access permission screen. I get a 11 - Login screen instead.

Thanks.
 

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Discussion Starter · #47 ·
Could you go thru the process you used again and take photos of the XTool screens you use ?

The reason I ask is because the 4B0 ECU I have gave me the SKC code easy enough but I couldn't log in to the ECU afterward.

Retrieving the SKC from a 4B0 is different that the 3B0 (V6) or the 07D (W8) that I have.

This is what I get when hooking up the XTool : View attachment 102552 View attachment 102553 View attachment 102554
With the 3B0, I have to enter a 4digit code first to get the SKC, and I don't have that 16 - Access permission screen. I get a 11 - Login screen instead.

Thanks.
I will document EVERYTHING! That way someone can tell me where I screwed up!
First of all I got exactly the same thing when I hooked up my X-tool. There were three options for getting the SKC. Only the engine option gave me anything and it read exactly the way that yours did. In the Engine screen it gave me the Immobilizer Code which I assumed was the SKC. That's as far as I got. I was planning to use the VCDS for everything else - I'm not sure if that makes a difference as to the response of the ECU. I have very detailed instructions to swap out an ECU using the VCDS. Maybe I'm not looking at the pictures right. Do you have a way to hook up the ECU to the Xtool outside of the car?
 

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Discussion Starter · #48 ·
I spent a few hours today preparing to do the big switch. I decided to disassemble the ECU compartment first and I'm glad I did because the first obstacle was that I didn't have a ratchet extension small enough to fit in the little hole they give you to get the back bolt off the cover. I tried to improvise a tool like so:
IMG_20210308_150311404.jpg

102570

That little bit of tape that I put on to hold the socket on was enough to make it too big to fit in the hole. Ugh. So I had to run out to get an extension that was the right size - It not only has to be small enough to fit through the hole but it can only be so long because the hood is in the way. I almost drilled the hole bigger but I headed out to Harbor Freight, consoling myself with fantasies of beating the crap out of the engineer that thought this up.

My next surprise: The ECU in the car did not match the number that I looked up to buy the new one:
This is the one in the car:
102571

This is the one that I bought:
102572


I'm going to try it anyway based on @Iowegian's statement that the last number is a version and should work.
In the meantime I've located one with almost all the same numbers on which the seller has already retrieved the PIN! I'll see if this one works first.
THANKS all for the help.
 

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Discussion Starter · #49 ·
Could you go thru the process you used again and take photos of the XTool screens you use ?

The reason I ask is because the 4B0 ECU I have gave me the SKC code easy enough but I couldn't log in to the ECU afterward.

Retrieving the SKC from a 4B0 is different that the 3B0 (V6) or the 07D (W8) that I have.

This is what I get when hooking up the XTool : View attachment 102552 View attachment 102553 View attachment 102554
With the 3B0, I have to enter a 4digit code first to get the SKC, and I don't have that 16 - Access permission screen. I get a 11 - Login screen instead.

Thanks.
OK Tort here's what I got - funny I got the code TWICE - you'll see. I ran through all the screens displaying what I got:
102573

102574

102575

102576

102577

Do you know what this Common password address is?
102578

01541 is the password for the first time. Not sure what the rest of the stuff is but the 00CC is one of the Common password addresses mentioned above!
102579
 

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Discussion Starter · #50 ·
@Tortelious Continued from the previous post which I closed inadvertently.
102580

OK since you already gave me the code once!
102581

102582

And there it is for the second time. I'm guessing that the password is the same for the dashboard and that's what I was seeing previously and that this version doesn't have a separate immobilizer unit - it's either built into the ECM or the Dashboard which are coded identically????
 

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Yes, the dashboard and ECU PIN codes will be the same, and both have their own Immobilizer unit. Those common addresses will give you different passwords. You can try all the Passat common addresses and jot down all the passwords. If you choose "Diagnosis systems" then "Engine", you will get a screen that offers a login option. Try all the 4-digit #s to see if it lets you in.
 

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Discussion Starter · #52 ·
Yes, the dashboard and ECU PIN codes will be the same, and both have their own Immobilizer unit. Those common addresses will give you different passwords. You can try all the Passat common addresses and jot down all the passwords. If you choose "Diagnosis systems" then "Engine", you will get a screen that offers a login option. Try all the 4-digit #s to see if it lets you in.
That is REALLY helpful. I'm finding the documentation for the V401 to be sadly poor. It seems like there should be a way to save info. It has a micro SD card and it shipped with a USB adapter for same. I can't see any connection to the operation of the thing. The manual spends more time telling you not to stick your hand into the fan or lick the battery terminals while standing in a puddle than it does on working the thing!
 

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That micro SD and adapter are only for upgrading. And licking the battery terminals while standing in a puddle is how you re-boot the XTool.
 

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Try this, it should work.

If using a new ECU.
Use XTool to retrieve the original SKC from the Instruments or ECU.
Then install the new ECU and use VCDS to enter the original SKC in the ECU.


If using a Used ECU.
Use XTool to retrieve the original SKC from the Instruments or original ECU.
Use XTool to retrieve the SKC from the (used) replacement ECU.
Then install the (used) replacement ECU and use its SKC in VCDS to unlock the ECU,
then in VCDS, go to Adaptation and enter the original SKC in the (used) replacement ECU.

Check the instructions on the Ross Tech site.
 

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Discussion Starter · #56 ·
Try this, it should work.

If using a new ECU.
Use XTool to retrieve the original SKC from the Instruments or ECU.
Then install the new ECU and use VCDS to enter the original SKC in the ECU.


If using a Used ECU.
Use XTool to retrieve the original SKC from the Instruments or original ECU.
Use XTool to retrieve the SKC from the (used) replacement ECU.
Then install the (used) replacement ECU and use its SKC in VCDS to unlock the ECU,
then in VCDS, go to Adaptation and enter the original SKC in the (used) replacement ECU.

Check the instructions on the Ross Tech site.
Thanks Tom I'm using the VCDS system simply because the documentation is better - It's a little easier to use and to document what I did as well but it follows the same route you outlined!
 

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Discussion Starter · #57 · (Edited)
I tried and failed to install the new ECU. When I entered the SKC in the new ECU it returned an error. Before I started the adaption I ran the numbers on the old ECU:
102610

I then uninstalled the old ECU and installed the new one. When I entered the SKC it returned an error:
102611

However it did read and change the serial numbers:
102612

The VCDS manual lists the following as a prerequisite:
  • All relevant coding and adaptation values have been transferred from the ORIGINAL (OLD) ECU to the REPLACEMENT (NEW) ECU.

    Did I miss a step?
 

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You need to enter the cars original VIN and Immobiliser serial number, in the replacement ECU (whether New or Used),
before entering the the original SKC.

I suggest you read the Ross Tech instructions again, and watch their video in the link you posted.
 

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Discussion Starter · #60 ·
Unless my eyes are playing tricks on me, the VINs and immobilizer #s didn't change. Me not having done this step yet, can you enter the correct #s manually ?

To double-check if you did it correctly, look at this, specifically page 6.
Good luck.
Thanks for this info Tort! Page 6 seems not to apply since, at least right now I'm installing a new ECU. I'll have a look anyway in case there's helpful info. I am also awaiting delivery of a used ECU, the part number of which matches the original exactly. I'd like to use the new one so I'm going to continue to attempt to get that to work. The silver lining is I LOVE driving my Jetta!
 
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