Passat 1996: Engine Stalling - Troubleshooting

Hi,

Since I'd like to try debugging something tomorrow, could you please provide some tips about the problem?

Passat, model year 1996, with a 1Z engine.
The engine starts, but almost immediately shuts off again, barely registering any movement on the tachometer.
After finally getting it to stay running after the tenth attempt, it runs wonderfully, and you can easily drive 100 kilometers on the highway without any problems. It has never stalled during a trip!

Relay 109? (Does it sometimes fail during operation?)
WFS??? (It runs for about 3 seconds.)
Control valve (could this be the one that's not opening?)

Chrisi.

Hello, that sounds like an immobilizer issue.
What happens if you've already driven a certain distance and then restart the engine? Does it behave the same way, or does the engine start immediately?

Yes, that really sounds like an immobilizer issue!

Well, actually, pay attention to that, because if it doesn't start again, the yellow key symbol for the WFS lights up in the instrument cluster (speedometer), and it happens to me from time to time.

After experiencing some issues, I let it idle for at least 10 minutes, then turned it off, smoked a cigarette, and it wouldn't start again.

Then it's probably the immobilizer. Try using a different key.
What kind of Passat do you have, a 35I or a 3B?

There's still a 35i available.

We've already tried a different key, and the funny thing is, the error memory is empty!
Normally, if the system doesn't recognize the key, an error message would appear.

Yes and no! In the older systems, there were still bugs that caused not everything to be logged.

If you can rule out relay 109, then the problem is likely with the WFS (Wireless Front-end System). Check if all the connections of the read coil are correct and if all connections to the ESP (Electronic Stability Program) are intact.

What kind of MKB (machine control box) does your machine have?

As far as I remember, the immobilizer in the 35i is separate and located near the headlight switch and the air vent on the left-hand side.
Loosen the two screws on the bracket from underneath (after removing the shelf).
The box will then be hanging down. Start the engine and tap it with a hammer while it's running, and it should start.
If that's the case, you need a new immobilizer.

On the 35i, as far as I remember, the immobilizer is separate and located approximately near the headlight switch and the air vent on the left-hand side.


You are right.


'Actually, it's something to pay attention to, because if it doesn't start again, the yellow key symbol for the WFS will light up on the instrument cluster (speedometer). It happens to me from time to time as well.'


Such a symbol will never light up on a 35i. It simply doesn't have that feature.