[tonemoz]

Yes, but when programming a new blank 434 key there are still no remote functions after unlocking using this method.

[muskatas]

I am having same situation with akl cas4 and 434mhz key. CA works,remote works but car starting only from emergency coil. Key is oem continental.

[willisodhiambo]

Yes, but when programming a new blank 434 key there are still no remote functions after unlocking using this method.

Explain how you did this.
1. Unlocked FEM
2. Made Key
3. Wrote ISN to fem
4. Make key again with ISN
 should work this way though never tried myself.

They say key crypto is made from ISN so key in 2 will not have correct crypto?

[Mwahab]

I don't know i am too outdated or i don't have proper knowledge, but if you used the option to make key in FEM without a WORKING KEY or DME ISN, ALL REMOTE FUNCTIONS WON'T WORK EVEN IF YOU MADE 9 KEYS AFTER THAT, ONLY EMERGENCY START.

[Inerceptor]

When unlocking with a working key - the crypto key is calculated from key.
In the variant "all keys are lost" it is necessary to generate a crypto key using isn DME and isn FEM.
this is EWS5-crypto system.

So after unlocking without working key, then matching Dme and Fem isn and programming new blank key should create crypto key? Or do I misunderstand?
Also, is there less security with 868 keys, as I said in first post, after converting to 868 all worked fine.
Is there a flaw in the tool?

Right! After unlocking without a working key, is it necessary to read the DME isn and use two isn to calculate the crypto key? After such a procedure, the factory keys, if they are later found, will not work!

868 keys were also FEM/BDC? And also the unlock was without a working key?

[tonemoz]

To clarify the procedure used:

Unlock donor ecu without working key or isn

Fit to vehicle and change FA and isn from DDE.

Program key using new blank key.

Unlock Fem again wih now working key.

Program 2nd key.

Still I have no remote functions. The last time I used this procedure and to solve I modified Fem to 868, changed the receiver for 868 and programmed new blank 868 key. This all worked.

So why not with 434 key?

Hope this explains everything.

[Mwahab]

You can never make it work like that SIR.

[tonemoz]

You can never make it work like that SIR.

So, makes the option of unlocking without working key pretty useless then?

Although it worked with an 868 key?

[Inerceptor]

Procedure "all keys are lost/do not work"
1. Unlock BDC/FEM
2. Read ISN DME
3. Invent any random cricto key (8 bytes, for example - 11 22 33 44 55 66 77 88)
4. Using this crypto key and the ISN DME that you read in step 2, calculate the new ISN FEM/BDC (I can help with this)
5. Write in FEM/BDC a new ISN, crypto key and ISN DME (all in DEcrypted format)
6. Make new keys using ISN DME

If your tool allows you to unlock FEM/BDC and DEcrypt data in it (with ISN DME)
1. Read ISN DME
2. Unlock FEM/BDC and get DEcrypted data (Crypto key, ISN FEM/BDC) using ISN DME
3. Make new keys using decrypted data

I hope everything is clear now)

---

You can never make it work like that SIR.

So, makes the option of unlocking without working key pretty useless then?

Although it worked with an 868 key?

How many cars have been successfully made with 868? Without keys.

[tonemoz]

Procedure "all keys are lost/do not work"
1. Unlock BDC/FEM
2. Read ISN DME
3. Invent any random cricto key (8 bytes, for example - 11 22 33 44 55 66 77 88)
4. Using this crypto key and the ISN DME that you read in step 2, calculate the new ISN FEM/BDC (I can help with this)
5. Write in FEM/BDC a new ISN, crypto key and ISN DME (all in DEcrypted format)
6. Make new keys using ISN DME

If your tool allows you to unlock FEM/BDC and DEcrypt data in it (with ISN DME)
1. Read ISN DME
2. Unlock FEM/BDC and get DEcrypted data (Crypto key, ISN FEM/BDC) using ISN DME
3. Make new keys using decrypted data

I hope everything is clear now)

---

You can never make it work like that SIR.

So, makes the option of unlocking without working key pretty useless then?

Although it worked with an 868 key?

How many cars have been successfully made with 868? Without keys.

Just one car so far using this method. To solve my latest problem I managed to source another Fem with matching 434 key. I have several spare Fems now without keys, would be nice to know if there was a way to make these usable on 434 cars.