Immobilizer A4 B5: MSTG Locked - How to Fix?

Good evening.

I have an Audi A4 B5 from 1995. After I went shopping, the car wouldn't start, and the immobilizer light was illuminated.
The error message is shown below.

Six weeks ago, I already brought the vehicle in because the interior was wet due to a clogged and overflowing water tank.
It was drained and, so far, there have been no further problems.

The engine control unit is dry, and the connection to the interior is also dry.
I charged the battery overnight because it was running low.

I can clear the errors in both the MSTG and the WFS, and then the icon for the WFS also disappears. However, when I restart, the icon lights up again, and the errors reappear.

Does anyone have any suggestions on where I could look, or has the MSTG (presumably a specific organization or project) been discontinued?

Regards,

Edit:

In MWB 1 of the WFS, all approvals are present, which means the WFS should be functioning. The key has been recognized, the MSTG response is available, and the start authorization has been granted.

VCDS Version: RKS 15.7.1. Runs on Windows XP x86.
Data as of: 20150914.
http://shop.dieselschrauber.de

Tuesday, December 01, 2015, 19:49:11:58542

Vehicle type: 8D - Audi A4/S4/RS4 B5 (1995 > 2001)
Scan: 01 02 03 08 15 16 17 25 35 37 45 55 56 57 67 75 76 77

Mileage: 102,830 km
"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
Address 01: Engine Control Unit
Label file: DRV\058-907-557-ADP.lbl
Part number: 8D0 907 557 B.
Component: 1.6L R4/2V MOTR HS D07
Encoding: 04001
Operating number: WSC 00000
VCID: 2F6B2594EDF9E246F4-4B64

"One error found:"
17978 - Engine control unit locked.
P1570 - 35-00 -
Readiness: Not Available.

"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
Address 03: Brake Electronics
Label file: DRV\4D0-907-379-ABS.lbl
Part number: 4D0 907 379 D
Component: ABS BOSCH 5, Part Number: 7402.
Operating number: BB 37402
VCID: 2F6B2594EDF9E246F4-515A

No error codes found.

"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
Address 08: Climate Control/Heating. Label file: DRV\8L0-820-043-2D.lbl
Part number: 8L0 820 043 D
Component: A4 CLIMATE CONTROL SYSTEM - FULLY AUTOMATIC - D75
Encoding: 04160
Operating number: WSC 06325
VCID: 295FCB8CD31D8C762A-25B8

8 error codes found:
00603 - Actuator motor for footwell/defrost flap (V85)
41-10 - Blocked or Unstressed - Sporadically.
01274 - Actuator for pressure relief valve (V71).
41-10 - Blocked or Unstressed - Sporadically.
00792 - Pressure switch for air conditioner (F129)
31-00 - Short circuit to ground / Interruption.
00532 - Power supply voltage.
07-00 - Signal too low.
01297 - Temperature sensor for footwell airflow (G192).
30-00 - Disconnection / Short circuit after positive terminal.
01296 - Sensor for exhaust temperature, center (G191).
30-00 - Disconnection / Short circuit after positive terminal.
01206 - Signal for ignition deactivation duration.
27-10 - implausible signal - sporadic.
01582 - Coolant temperature sensor signal.
30-00 - Disconnection / Short circuit after positive terminal.

"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
Address 15: Airbag
Label file: DRV\8A0-959-655.lbl
Part number: 8A0 959 655 C
Component: Airbag, V, AUDI D00.
Encoding: 01022
Operating number: WSC 33977
VCID: 336329E401D1C6A690-5178

"One error found:"
00532 - Power supply voltage.
07-10 - Signal too weak - Sporadic.

"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
Address 17: Control panel module
Label file: DRV\8D0-919-0xx-17.lbl
Part number: 8D0 919 033 C.
Component: B5_COMBINATION_INSTRUMENT D02
Encoding: 00142
Operating number: WSC 06311
VCID: 2859CE88C817B57E35-4B00

No error codes found.

"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
Address 25: Immobilizer
Label file: DRV\4A0-953-234.lbl
Part number: 4A0 953 234.
Part number: IMMO AUZ9Z0S0212298 D76
Encoding: 00000
Operating number: WSC 76783.
VCID: 5FCB9554DDD932C604-5178

"One error found:"
01177 - Engine Control Unit.
65-10 - unauthorized - occasional.

End----------------------------(Duration: 04:44)-----------------------------

I seem to recall that the contact issues at the cable connector of the reading head assembly were partly due to problems with the connection itself.

I am familiar with this error. However, wouldn't the key actually be registered as "not recognized" in the vehicle's control unit memory?
As mentioned in the MWB 1 document, all necessary approvals for engine start are in place.

Quote:

As mentioned in the MWB 1, all approvals for engine start are in place.

...and that's always the case, so it can be ruled out that the ignition key is occasionally not recognized?

If you take the second key, does it work the same way?

Morning.
Yes and yes .

Hi,

Two weeks ago, we had a similar Passat model here with similar symptoms.
In addition to that, there was a problem where it sometimes wouldn't start. It would just turn on and then immediately shut off again.
Then, the error related to the locked MSG could be cleared, the light went out again, and the system started up perfectly. The relevant WFS modules also showed no issues.
"Sometimes, it would still show the error 'Key not authorized' or something similar, but not always. Then, sometimes the WFS light would come on during the drive, but it wouldn't turn off."
When he ran, he just ran. Only the lamp was on, and that was the case with both keys.

In his case, it was the reading head.

Hi,
Today, I replaced the cable between the reading coil and the WFS control unit, and also the ignition switch because it was broken.
Unfortunately, both attempts were unsuccessful.
Both errors can be cleared from the control units, but the warning light for the WFS (likely referring to a specific system) goes out, yet the vehicle still doesn't start.
My suspicion is that there is a faulty MSTG.

Does anyone have any other suggestions?
Thank you.

Reading coil, as Steffen writes about it, or a WFS control unit.

I can't imagine that being a motor control unit.

Evening.
I installed and configured a different WFS control unit earlier, and it was working. I then reinstalled the old one, erased all the learning values again, and now it's working again.

Unfortunately, I can't say for sure what the exact cause was.
It's possible that the MSTG has forgotten the values . The battery is very weak; it's been sitting for a month, and the range is only 500 meters }.

Strange...... and Thank you for the feedback