VW Volksiebus 2.3i Factory Fitted Immobiliser

Immobiliser Unit outside

437FT0217 VW / Audi 22S 907 044 Immobilizer Unit

Immobiliser PCB top view

Top view. It's a lot of components for a simple function. The PIC16C57 processor is labelled "VWKL VN1.3", I would speculate that the working name for this unit is most likely "VWKL" and the firmware is obviously V1.3. Resonator is 4 MHz. The V23026-D1025-B201 relay is from Siemens, it's a SPDT unit with a 9V coil. The chip at the top left is an L4949 5V regulator, and the transistors are marked "5Cp" and "6C" which makes them BC807 and BC817 respectively.

There's some serious wierdness with the little 8 pin chip below the PIC though. It's marked "105-T" and "8889" and the logo looks a bit like

and I can't find any info on it. It's only connected to 0V and to the PIC via two lines, no connection to power that I can see.

Immobiliser PCB bottom view

"VWKL000802" -- I'm guessing this is the serial number, it loosely ties in with the VIN number -- remember that vehicles with electric windows have a different immobiliser. PCB is marked

"437AW0055 REV 33"

Immobiliser PCB with relay removed

Immobiliser PCB with relay removed. Only the normally-closed contact are used. Presumably the immobiliser fails "safe" so that when the PIC doesn't come up, it never powers up the relay and that bypasses the immobiliser.

The connector is marked "AMP" and is a 0.1" pitch 2 x 6 pin unit. Havn't been able to find a part number yet, so I arbitrarily numbered the pins

1  2  3  4  5  6
7  8  9 10 11 12
Looking into the PCB mounted connector with the component side up.
1   N/C
2   gnd
3   ignition
4   +12V
5   LED
6   dongle R
7   dongle C
8   gnd - dongle L
9   relay
10  relay
11  N/C
12  gnd

Immobilised immobiliser

For the record, this is one way of immobilising the immobiliser, while still keeping the blinking LED on the steering column.

[Image] Hit Count hits since 2017-06-25.

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