VW LT35 Immobiliser issues

   #1  

Zander

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VCDS Serial number
HC150997 (NIF)
Hi all, I have a 2006 VW LT35 with the 158 engine (AUH). The immobiliser problems started after I did the head gasket on it because it was loosing compression. I went to start it for the very first time after putting the head back on and it took a while to start but eventually did, test drove it and it was fine. The next day i went to take it for another run and it wouldn't start. Went through the procedures and found that there was no fuel at the injectors. So I tried and tried to get fuel up to the injectors but no luck. Gave up and left it, next time I tried it started perfectly and ran. Time after that, did not. So i decided to scan it and found the faults listed in the scan.

** The van has 2 genuine original VW keys. Except one has a crack across the key and one has snapped in half, so we have a generic key that we got cut and has worked fine for the past 100, 000 miles. And this is what the "Unauthorised" key is. It rarely threw up a fault and always started second time.**

Code:
Chassis Type: 2D - VW LT2 (1996 > 2006)
Scan: 01 25

-------------------------------------------------------------------------------
Address 01: Engine        Labels: None
   Part No: 2D0 906 019 A
   Component:  2,8l R4 EDC 0001SG  3713
   Coding: 00002
   Shop #: WSC 02330
   VCID: 20412E56A0BF0B8422-4B00

1 Fault Found:
17978 - Engine Start Blocked by Immobilizer
            P1570 - 35-00 -
Readiness: N/A

-------------------------------------------------------------------------------
Address 25: Immobilizer        Labels: 6N0-953-257.lbl
   Part No: 2D0 953 257
   Component: IMMO VWZ4Z0E0036407 V00
   Coding: 09600
   Shop #: WSC 02330
   VCID: 65CF7F42FF1D2EAC91-4B00

2 Faults Found:
01176 - Key
            07-10 - Signal too Low - Intermittent
01176 - Key
            65-10 - Unauthorized - Intermittent

End-------------------------(Elapsed Time: 00:15)--------------------------

Since the van now won't start at all, I decided to check the system. I checked plugs/fuses/wiring and found nothing wrong. I then checked for voltage through the system using a wiring diagram from ERWIN. I'm getting 12V where I should be and continuity from the earth wires to earth. There is 2 wires from the reader coil going into the Immobiliser control unit. one brown and one black. Both produce no voltage until your cranking the engine then they will give between 0.3V and 0.38V. Is this a strong signal? I've done this with both the original key and the generic one, same results for both.

I read an article on the Ross-Tech website (http://wiki.ross-tech.com/wiki/index.php/Immobilizer) so I thought I would give the Key matching a go. This is where i think I have gone wrong...
I opened the immobilser section (25) on VCDS and clicked on coding and this screen appeared (can't seem to attach photos) it says Recode Module at the top then in an information bubble it says Immobiliser (J362) Coding and displays 2 codes, one for diesel and one for petrol. So I left that page because I didn't know what to do but ever since I can't communicate with the immobiliser! It has many attempts and the come up with"VCDS: Session Unreliable" and "Too many Communication errors to continue!" Is it possible I have upset the control module (J362)? How could I get access back into it to maybe recode?

*One thing i have noticed is that if you leave the ignition on, with out cranking, after maybe a minute or 2 the glow plug light will start flashing, but have not seen the immobiliser light at all.

Thanks for any help given as I am completely stuck now!!

Code:
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 7 x64
VCDS Version: 20.12.0.1 (x64)
Data version: 20201125 DS322.1
www.Ross-Tech.com


VIN: WV1ZZZ2DZ6H024218

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


Chassis Type: 2D - VW LT2 (1996 > 2006)
Scan: 01 25

-------------------------------------------------------------------------------
Address 01: Engine        Labels: None
   Part No: 2D0 906 019 A
   Component:  2,8l R4 EDC 0001SG  3713 
   Coding: 00002
   Shop #: WSC 02330 
   VCID: 20412E56A0BF0B8422-4AE6

1 Fault Found:
17978 - Engine Start Blocked by Immobilizer
            P1570 - 35-00 -
Readiness: N/A

-------------------------------------------------------------------------------
Address 25: Immobilizer        Labels:
   VCID: 55AF4F82AC7DBE2C01-12BA
   Note: Excessive Comm Errors


End-------------------------(Elapsed Time: 00:49)--------------------------
 
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   #2  

Uwe

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HC100001
Immobilizer module starting to fail?
Check connections at immobilizer module and between immobilizer module and pickup coil.

If it my 15 year old van was giving me these problems (I actually have a 20 year old T4 van), I would send the ECU out for an immobilizer defeat and never worry about it again.

-Uwe-
 
   #3  

Zander

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HC150997 (NIF)
I’ve checked the connections from the pick up coil to the immobiliser Module. I like to try and fix the issues rather than just delete the problem but if it’s going to be failing units I probably will delete as it’s much much cheaper. Is it possible to delete the immobiliser from the ECU using VCDS?
 
   #4  

Uwe

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