Automatic & Diagnostic Issues

Hi,

Golf 3 with a 4-speed automatic transmission, manufactured in 1994, had a persistent error message 'Multifunction switch: implausible signal' and occasionally shifted sporadically, for example, from 4th to 3rd gear on the highway, or from 2nd to 4th gear in city traffic.

After the control unit was disconnected and reconnected, and possibly connected incorrectly once (the instrument cluster beeped, and the control unit made clicking noises), the following occurs when the automatic transmission control unit is connected:

The vehicle stalls when braking/coming to a stop (the engine turns off).
The gears aren't shifting properly anymore! It won't come out of first gear!
Neither the automatic transmission control unit (STG) nor the engine control unit (STG) are diagnosable anymore.

If you disconnect the automatic transmission control unit, then...
Likely an emergency mode (1st and 2nd gears are engaged, 3rd and 4th are not).
Engine control unit is now diagnosable.

Questions:
a) Is the control unit broken? I think so! Ugh, it's so expensive!
b) Why is the M-control unit not diagnosable when the A-control unit is connected?
c) Can someone explain the exact function of relay 150? It's supposed to be for the starter and gear selector lock, but that doesn't seem to be working anymore. Also, I've noticed that the engine briefly revs up when the relay clicks (in position N). Why does it click when in position N, but not when in position D?
Could this possibly be related?

HELP!!! Does anyone have a wiring diagram???

Chrisi.

Deleted upon request.

Oh... yes, I remember that... it's nice that someone still thinks about it.
Let's hope so!

Chrisi.

b) Why is the M-module not diagnosable when the A-module is connected?

Possibly, the A-STG is blocking the K-line. This could mean that it is completely broken .

Oh no... can anything else possibly break?
Or will the error be gone with the new control unit?
'The instrument cluster isn't diagnostic-capable! So, there's no connection, and I'm asking because it's also beeping!'

He has airbags, but the warning light remains on!

Chrisi.

b) Why is the M-module not diagnosable when the A-module is connected?

A friend of mine once had a faulty climate control control unit. When I tried to diagnose the problem, I couldn't access any control units. As soon as I disconnected the climate control unit, I could access all the other control units again.

It seems 'normal' when a control unit is completely broken.

How did you have the A-STG 'incorrectly connected'?

Hi,

I replaced the automatic transmission control module, and now the diagnostic system is working again.

But they are being discarded:

Multifunction switch, undefined switch state.
and occasionally:
Gang monitoring - implausible signal!

The car still jolts and shakes terribly at times.
What has also been noted is:
Once the fault is resolved, the immobilizer (also known as the foot brake interlock) is deactivated. We have also already replaced the starter relay.


Already appeared:
Select 'D' on the gear selector and stop at a red light – sometimes it's fine, but sometimes it goes haywire, jerks around, the RPMs spike, and so on...

And it just won't go away, even though the switch is brand new!!!

Driving on the highway is not possible... at 130 km/h, it shakes so much that it feels like you're at a rock concert!

Also, I've noticed something three times now when the engine is misbehaving: all the measurement blocks I'm currently viewing with VAGCOM suddenly display '00000' everywhere. Then, in the next second, they all reappear.

Do you have any suggestions/ideas?

Do you have any suggestions / ideas?


Thoroughly inspect the entire wiring harness.

CHECK ALL CONNECTORS...


CU Gremlin.

Hello Chrisi,
Please provide the part number of the automatic transmission control unit (STG), the error codes, and the transmission identification letter.
It makes it easier to find documents (at least for me, in my pile of data ).

Best regards, Rudi.

Hi,

STG: 096 927 731 BK
Identification letter: CFK.
Error: Multifunction switch - undefined switch state + gear monitoring - implausible/sporadic signal... I think that's what it said.

I think there might be a missing component or something. Someone mentioned there might be an additional fuse somewhere, but they didn't know where it was. They just said that there's supposed to be another one somewhere that might be responsible.

Chrisi.

Okay, then I will start searching .

Best regards, Rudi.

So... you've got mail!

Let me know when you've made progress.

Best regards, Rudi.

P.S. You don't drive a diesel car, do you?

P.S. You don't drive a diesel car, do you?

Öhhhmmmmmm