Emergency Mode: Reproducible Based on Outside Temperature

Volkswagen Golf III TDI, 110 horsepower, manufactured in 1996, with a VTG turbocharger.

Hello,

The following problem occurs consistently (for the past 2 years) and exclusively when the outside temperature is above approximately 20°C.

Beim Beschleunigen im 5. Gang (Hochschalten ab ca. 2.800 RPM) fällt die Motorsteuerung in ein Notlaufprogramm und das Fahrzeug fährt nur noch 120-130km/h. Nach kurzzeitigem Ausschalten ist der Fehler weg und der Motor zieht wie gewohnt. Ist es nicht wärmer als 20° kann durch Beschleunigen im 4. Gang bis 4.200 RPM diese Problemzone umgangen werden und dann die Höchstgeschwindigkeit im 5. Gang erreicht werden. Ist es wärmer so tritt das geschilderte Problem auch im 4. GanSure, here is the translation of the text from German to English:

'g auf.'

This phrase is a shortened version of the German phrase 'geöffnet,' which means 'open.' It is often used in informal contexts, such as when someone is telling someone else that a store or business is open.

'When the temperature is below 20°C, the car functions perfectly, so last winter I had already started to believe in a miraculous fix.'

The mass airflow sensor and the charge air temperature sensor have already been replaced (unsuccessfully). The variable turbine geometry (VTG) adjustment mechanism moves smoothly without jerking or sticking (both when hot and cold). Disconnecting the (power) cable of the VTG solenoid valve causes the adjustment lever to immediately move downwards at idle (<0.5 seconds).

Die Abgasrückführung habe ich probehalber deaktiviert (Abziehen des Unterdruckschlauches an der Dose). LUnfortunately, it was unsuccessful.

For the past few days, I've suspected that the engine control unit, and specifically the built-in boost pressure sensor, is not functioning reliably when it gets warm. My reasoning is:

When it's sunny (above 20°C), the car performs particularly poorly when the air conditioning is set to recirculate. Possible explanation: In recirculating mode, the airflow that normally enters from below the windshield wiper, passes over the control unit, and is drawn in through the pollen filter on the left side is eliminated. This means the control unit gets warmer. When I turn off the recirculating mode, the situation improves slightly.

Has anyone of you heard of a similar problem that is dependent on temperature?
Does anyone know if the control unit can be opened without causing damage?
Has anyone already replaced the pressure sensor from the control unit?
How can I obtain (Bosch?) components, specifically a pressure sensor?

Best regards,
Marcus.

Hello,

What does the error memory contain? There should be an entry related to the emergency mode.

Hello Michael II,

The workshop wouldn't tell me what the problem was when I asked. After having spent a considerable amount of money there, I have absolutely no interest in this expensive and useless service. Unfortunately, I don't have access to a VAGCOM device.

Best regards,

Marcus.

Hello,

It can be quite expensive to start a parts-swapping frenzy without any prior planning.
If your workshop refuses to give you the diagnostic report (which I find strange, as this is usually not a problem and is also stipulated in the VAG regulations), then I would go to a different one. Reading out a control unit should cost you around 5€, which is a very reasonable price.

Maybe you should try using the search function sometime. There's a lot of information here about emergency procedures and performance issues...

Hello,

'I'm experiencing the same problem at high outside temperatures. When fully loaded with a caravan and encountering an incline, it triggers the emergency mode! This only happens when all those factors occur simultaneously. For example, in the winter, the problem didn't occur even with a caravan attached.'

'I extended the support rod of the VTG three weeks ago. The consequence was lower turbo pressure and the emergency program no longer worked, but the overall power output was reduced. This meant a lot of gear shifting, even though the wagon usually handled most inclines without any problems in 5th gear.'

Hopefully, someone has an idea for troubleshooting this problem...

Hello!

The described problem, where the motor switches to a failsafe mode under load changes when the outside temperature is high, has been resolved.

However, VW was unable to make substantial contributions to resolving the issue. After a fruitless but costly replacement of the mass airflow sensor, the next step was to replace the engine control unit.

However, a self-diagnosis using VAG-COM revealed a significant discrepancy between the target and actual boost pressure at high temperatures. Furthermore, the duty cycle of the VTG control valve was extremely high compared to a similar Golf model.

Conclusion: Replacing the VTG vacuum control valve resolved the issue.

The error code read:
00575 - Intake Manifold Pressure
17-10 - Control Difference - Intermittent

Best regards,

Marcus.

UPDATE: Dieselmartin kindly incorporated my boost pressure curves, BEFORE and AFTER replacing the VTG control valve, as graphics into the forum (I was unfortunately unable to insert images myself) - Thank you very much.

The images are located 3 posts down!

Hello,

I was also able to describe exactly the same phenomenon.
On my car (same model), the error code was something like 'Intake manifold pressure regulation difference' or similar.
Okay, presumably the same text in terms of meaning.
However, it gradually faded away, and the following summer brought no more difficulties.

Greetings.

@Above

Well, the errors sound similar because the text is simply a translation.

The really important thing is 00575 (the error number).
The text will only be written into the VAGCOM system, and if an English version is attached, it will be in English.

You can also find possible causes here in the forum using that number.

And since the errors are no longer occurring, everyone is happy .

m;

Here are Marcus' logs.

dieselmartin wrote:

@Top Well, the errors sound similar because the text is simply a translation. The really important thing is 00575 (the error number). The text will only be written into the VAGCOM system, and if you attach an English version to it, it will be in English. m;

Hello.

The text is also located in section 1551. At least, that's where it is for me. It shouldn't be too difficult for VW people to find such an error, even if things are happening outside as described above.


Best regards, Cosi.