I'm running late. | Posts 16+

Hi,
Unfortunately, I only saw this post today, so I'll just add my two cents. I had a similar problem with a 1998 Golf 4 AGR (engine...). It would suddenly die with the oil pressure warning light flashing and everything. It always happened during the warm-up phase. After replacing the relay and ignition switch (without success), a new power cable was run from the fuse to the control unit – and that fixed it perfectly! According to the VAG expert, the suggestion for this came from the factory ( )… so, a known problem?

Hello everyone,

Thank you very much for your advice.
Until yesterday, I was, for reasons unknown, spared from that error. Fortunately, I haven't reinstalled the test setup with the LED yet.
Since I drove over a pothole-ridden road last night, the problem has reappeared immediately. For the first time, directly after the initial, more significant tremors.

For diagnosis: When the error occurs, the LED is on, indicating a lack of grounding from the MSG (Main System Ground).
The LED does not flicker. Therefore, it essentially switches on and off "hard." (as always - on after approximately 90 seconds.)
Turning the ignition off and on again has no effect; the LED remains on for its specified duration.
What I also noticed: During the malfunction, there is no tachometer signal and no engine speed signal. (Next time, I'll check the fuel sensor and temperature sensor , I unfortunately didn't think of that).
The speedometer and tachometer should also be sourced from the main system control unit (MSG).

Unfortunately, I haven't heard anything yet from the company that handles my pre-heating system.

To test it, I just bought an identical MSG on eBay (for 100 Euros, and that as a poor student ), but I think I'm wiser now.
Either everything will work properly after the installation, or the next step will be to install a new power supply line to the MSG. (Which one was it in your case, if you know? I'm guessing it was a 15 amp one.)

Regards,
Bodo.

Strange wrote:

When the error occurs, the LED is on, which indicates a lack of grounding from the MSG. The LED does not flicker. Therefore, it essentially switches on and off "hard." (as always - on after approximately 90 seconds.) Turning the ignition off and on does nothing; the LED remains on for its specified duration.

Hi Bodo,
So, it's like a countdown that always runs for the same duration, during which a restart of the engine is not possible?

Quote:

What I also noticed: During the malfunction, there is no tachometer signal and no engine speed signal. (Next time, I will check the fuel sensor and the temperature sensor , I unfortunately didn't think of that). The speedometer and tachometer should also be coming from the MSG.

DZM yes, but the speed sensor directly feeds the speedometer. The signal doesn't initially pass through the engine control unit (which, in turn, receives the processed speed signal from the speedometer!).
However, the hall-effect speed sensor also receives its power supply via the 109th pin. If that component fails, there will be no more drive pulses -> speedometer = zero.

However, the fuel gauge and temperature display should continue to function, as the instrument panel is directly connected to system 15.

Exactly, it's like a countdown.
Only if it's not related to heat... what is MSG trying to tell me with that?
Or, better yet, what purpose did the device's creator intend for it?

Strange wrote:

Exactly, it's like a countdown. Only if it's not related to heat... what is MSG trying to tell me with that? Or, better yet, what purpose did the creator of the device intend for it?

Hm,

When I turn off my engine, I only hear the characteristic "click" sound of the 109 about 3 seconds later. Only then does the engine control unit completely shut down.

If you repeatedly turn the ignition on and off very quickly (faster than the 3 seconds, which is a very long time...), it's possible that your engine control unit (ECU) remains active and prevents the engine from restarting for exactly 90 seconds (perhaps for safety reasons...).

Listen carefully to see if you can hear the delayed click (the "109" sound) when you normally park the car. And next time the car fails to start, leave the ignition off for a bit longer before attempting to start it again.

Otherwise, for me, the topic of (fluctuations in the) DWA (vehicle security system) is not entirely resolved - if it can block the engine computer in the event of an alarm .

Hi,

UPDATE: Finally, something really new

I got myself an identical control unit to see if it would solve my problem. The good part arrived yesterday, and I immediately installed it.
Result: Everything is exactly the same as before. No preheating display, and (to my delight), it shut off again immediately with the new MSG. Otherwise, no problems as before.

Regarding the preheating: I've checked it again, and it's preheating (at least for now), but it's not indicating that it is. That's why I immediately went to the dealership and got the corresponding connector pin assignments (the printer at the dealership was broken). The cable from the MSG (Main System Module) to the central electrical system has 100% continuity. There are also tensions present, but I don't really understand them at the moment; the instrument panel will probably understand .
Unfortunately, I couldn't continue testing due to the lack of a wiring diagram, but it sounds like there might be a break in the control circuit.

Also, I also took the opportunity to fiddle with my wiring harness while the engine was running (since the water box was already open). I couldn't get it to shut off. Okay, another point for ZE.

Anyway, I ended up reinstalling my old control unit, and I've now dismissed my suspicion about the instrument cluster.

Does anyone happen to have one they're selling at a good price?

Regards,
Bodo.

Okay, regarding the ignition:
I've already experienced a situation where it shut down for about 1 second, similar to a normal glitch, but then it recovered.
The thing about waiting (5 seconds) during the restart sometimes helps.
Often, the MSG then provides power again (LED turns off). The LED remains off even when the ignition is turned on. As soon as the starter is engaged, it turns on again.
Until it eventually turns off.

My 109 actually disconnects by turning the ignition key.

Strange wrote:

The thing about waiting (5 seconds) during the restart sometimes helps. Often, the MSG then provides power again (LED turns off). The LED remains off even when the ignition is turned on. As soon as the starter is engaged, it turns on again. Until it eventually turns off.

Hi.

It's getting better and better... The starter motor and "109" have absolutely nothing to do with each other!

I can only imagine the following:
A weak point or intermittent connection somewhere in the wiring between the battery and the ignition switch, or within the ignition switch assembly itself.
When engaging the starter, a significant amount of current flows through the ignition switch, which can cause a voltage drop at that point. This voltage drop can be so severe that the engine control unit (ECU) "disregards" the remaining voltage or that the voltage is no longer sufficient to activate the gear selector for the 109.

Could you please measure the voltage on pin 15 while the starter is running?
Or even better, the voltage at the ZE terminal, plug G 1/4 = activation wire for the motor computer?

Do you know now whether and how the DWA (Deutsches Wasserstoffstrategie-Allianz) can disable the engine?

Hi,

Unfortunately, I don't have a multimeter handy right now, but I should be able to get it sorted out by tomorrow.
To make things a bit more complicated: In my completely subjective opinion, I would say that more glitches occur in warm weather. (The patient has all the symptoms of all diseases )... but this is purely subjective. Perhaps I simply get more annoyed when I'm standing on the street at 30° .

We can pretty much rule out the MSG itself at this point. (see above)
By the way, the ignition switch itself is also new, so it's more likely to be the wiring or the control unit.
I haven't looked into the DWA yet, but I'll find out more when I pick up the schematics.

Hello,

I'm still following the topic with great interest. It's really frustrating how hidden an error can sometimes be and how many possible causes there can be.

Strange: Have you received the engine control unit you bid on yet?

Best regards and good luck.

Hi,

I'm (again) having the same problem. Passat 35i / '94.

The first solution was to replace the DWA, as a relay on the circuit board had become cold-soldered due to vibration (a lack of manufacturing quality, as is often the case with this type of electrical equipment ). This relay, if it randomly fails while in operation, causes the symptoms described: engine shutdown, the indicator light remains on continuously (for longer than 1 second), a wait of 1-2 minutes, and then a restart is possible...

With a keen eye, you can identify a cold solder joint by carefully wiggling the heavier components and closely observing the solder joints.

Anyway, the first year went great! Until yesterday, when I had to solder the voltage regulator on the control board again (and this time, I installed a proper heat sink for it). The DWA board still looks perfect! Now I have to go through the whole process again: REL109, motor control, contacts, etc. First, though, I'm going to build the LED – a great tip!

CU
Romeo.

Okay, then I'll probably go fishing again tomorrow.
The LED is really great for this problem, and as a side benefit, you know when you can restart.
I completely agree with you - great idea, ulf!
If I've already measured them, here are my voltage readings:
Ignition: 12.6V
With starter: minimum 10.4V.
With the engine running: 13.8V.

This doesn't quite explain the problem with the preheating indicator yet, but one thing at a time... *Soldering iron burn*

/viewtopic.php?t=3358&highlight=kalte

Best regards, Rainer.

Hi,

Since I resoldered the entire control unit for the DWA (which isn't that much, really) the day before yesterday, I haven't had any more problems with glitches.
I probably missed a loose solder joint the first time. Let's just hope that was the reason.
The preheating indicator is still not working...

Let's see how long he stays fit.
So far, thank you very much, everyone .

Regards,
Bodo.

Hi,

The complete control unit for the alarm system has been resoldered.
The beauty of it is that you can fix 80% of the problems with a Phillips head screwdriver and a soldering iron .
Hopefully, it will last for a while now!

The preheating indicator is still not working...

Perhaps this will work.
If you remove REL 109, you will have a constant voltage on the glow LED (in an otherwise bug-free state with the ignition key on). This gives you more time (>1s ) to measure the voltage levels. The LED is likely controlled by the control unit (X1/48?). However, I haven't yet conducted any long-term tests to assess potential side effects.

CU
Romeo.

Hi,

It's highly likely that DWA was responsible. After driving a slightly longer distance today and not experiencing any other issues, I think the problem has been resolved.

Quote:

If you remove the REL 109, the glow LED will constantly have voltage (in an otherwise bug-free state with the ignition key on).

Taking the 109 out already points us in a certain direction... because even without the 109 and with the ignition turned on, the lamp remains off.

Regards,
Bodo.